Short answer: Yes

The proper answer: While Luo Guanzhong's (fun and entertaining) novel is the version of the era that many are familiar with, one has inspired works that have followed, it was far from the first work of fiction and the era far from forgotten. Diao Chan, Zhou Cang, Guan Suo were not creations of the novel, Guan Yu's 1,000 li journey to return to Liu Bei, the Peach Garden Oath or Lady Sun loving Liu Bei were not his ideas. His novel drew upon many tales that had come before and knitted them into a (somewhat) cohesive narrative.

Some figures' legacy lasted long after their deaths: Zhuge Liang was worshipped within Yi upon his death, in the Jin dynasty his home in Nanyang became a place to visit and he was eulogized. Liu Biao for centuries retained popularity among Jing figures including legends of his body not decaying. By the time of the Liu-Song dynasty, Pei Songzhi was able to include some... unreliable accounts of the era, commentary and ghost stories to add to the records. While Prince Liu Yiqing was involved in the A New Account of the Tales of the World/Shishuo Xinyu which, while the Jin dynasty is the main focus, included tales of the Wei court like the Cao family, Xun Can, Yang Xiu, Ni Heng and others.

Rulers could draw upon the legitimacy of Wei or Shu with Han-Zhao's Liu Yuan drawing upon Shu-Han via his claims for Han lineage. Scholars argued who had the mandate with Eastern Jin's Xi Zuochi was the first to push against Jin's claim of Wei while Song scholar Zhu Xi helped push that legitimacy argument. Others sought to promote their local areas via the kingdom that had once ruled, poems like that of Cao Zhi were collected. There were temples, including perhaps somewhat oddly one for Cao Cao deep in the former lands of Shu-Han in present-day Luzhao.

We don't hear anything on circulation among the common people of tales till the Tang era and Li Shangying talked of his son compared his guests to the barbarous Zhang Fei and the stammering Deng Ai. The Southern Song poet Su Shi/Dongpo wrote about Zhou Yu at Chibi but mentions a friend Wang Peng telling of youngsters going to hear a storyteller

When they hear of Liu Xuande (Bei) being defeated, they frown and even cry: but when Cao Cao loses, they shout for joy. One can see from this that the effect of a true gentleman or that of a mean fellow may be felt for a hundred generations without interruption.

This doesn't mean there weren't stories but while tales of wit and wordplay among the gentry sometimes survived for posterity or at least for potential mention. However, the tales from oral storytellers towards the poorer people did not always survive in the records, even if the children knew them well. The twelfth-century storyteller Huo Sijiu was famed for his tales from the era but little is known, the later Jin had four known plays (To Kill Dong Zhuo, Cursing Lu Bu, Meeting at Xiangyang and Slaughter at the Red Cliffs). There would be more during the Yuan and Ming eras: "Burning The Camp At Bowang", "A Lone Journey of a Thousand li", "the Pomegranate Garden", often with themes where Liu Bei trumps over Cao Cao (or representatives like Zhang Liao and Xiahou Dun). Or A Dream of Western Shu, Single Sword Meeting, various versions of three brothers fighting Lu Bu.

One work that survives is the Yuan dynasty Sanguo Zhi Pinghua/Records Of the Three Kingdoms in Plain Language, part of a series of history dramas. This one with Emperor Xian and three dynastic Emperors being the reincarnation of key figures in the founding of the Former Han, has the famed borrowing arrows story (but with Zhou Yu instead of Zhuge Liang), the peach garden oath, Zhang Fei's rivalry with Lu Bu. Other plays of the Ming and Yuan dynasties would follow similar themes as the Pinghua, suggesting that some of the tales were commonplace.

Guan Yu had long been worshipped in Jing, possibly initially as a way of keeping his spirit from seeking vengeance for the manner of his death, the Tang dynasty was the first to begin sacrifices at a more national level (as one of seventy-two generals sacrificed to) while Guan Yu's connection to Buddhism started with links to Zhiyi in the Tang dynasty. As dynasties passed, more temples were accepted and then even created and the links with religions (first Buddhism then Taoism) grew stronger as they sought to tap into his popularity, in the Song dynasty he became a deity. When the novel has Guan Yu being friends with men of religion, his manifesting as a spirit at Jade Spring Mountain and turning up after his death to other battles, the red face, the novel was tapping into something that was already there.

Likewise, some of the tales the novel tells about Guan Yu was borrowed from other works: Guan Yu killing a corrupt magistrate, the peach garden oath, the three brothers vs Lu Bu, the three conditions to surrender, the killing of Wen Chou (and the danger this puts Liu Bei in), nearly fighting Zhang Fei and slaying of Cai Yang, the connection with Red Hare. The loyal follower Zhou Cang (without the cannibalistic noble sacrifice) is included while the fictional third son Guan Suo gets a very brief nod though the novel doesn't borrow much from the tales of the fictional son.

Sometimes, when people get frustrated with the amount of fiction around the era or dislike a (usually Shu-Han) figure who is lionized, the novel gets blamed. However the novel didn't exist in a vacuum, there had been centuries of political legitimacy changes, of tales among the literary elite and among oral storytellers to the public that had been enjoyed and shaped perceptions, which the novel built upon. Fiction had long entered people's understanding of the era and its people, Shu-Han figures had long been subject to plays, worship and tales.

I hope this helped

Sources:

Shi-Shou Hsin-Yu: A New Account of Tales of the World by Liu Yiqing, translated by Richard B.Mather

Imperial Warlord: A Biography of Cao Cao 155-200 AD by Rafe De Crespigny

The Life and Legacy of Liu Biao: Governor, Warlord and Imperial Pretender in Late Han China by Andrew Chittick

Inventing the Romantic Kingdom by Simon Shen

Zhang Fei in Yuan Vernacular Literature: Legend, Heroism, and History in the Reproduction of the Three Kingdoms Story Cycle by Kimberly Besio

Making the Guan Yu Cult: The Rise of Guan Yu in National Sacrifice, Buddhism and Taoism by Li Teng

Guan Yu’s life after death: The religious and literary images of the Three Kingdoms hero Guan Yu by Jesper Timmerman

Historic Analogies and Evaluative Judgements: Zhuge Liang as Portrayed in Chen Shou's"Chronicle of the Three Kingdoms" and Pei Songzhi's Commentary by Hoyt Cleveland Tillman