The short answer is "no, but many claimed this after the war." The longer answer is complicated.

In July 1945, there weren't any American military or intelligence officials who thought the war would definitely be over soon. Or that the atomic bombs would end the war. Or that the war would end without an invasion. There were hopes that Japan was "on the ropes," and decrypted intercepts of Japanese foreign transmissions (known as "MAGIC") indicated that the Japanese Supreme War Council had divisions in it that might be exploited, the general conclusion was that while Japan was certainly near military defeat, it wasn't necessarily near political surrender. And there is a big difference between the two.

There was some enthusiasm for the idea that Japan would not last long if the Soviet Union declared war on them, but that is about the closest one gets to such a sentiment, and even that is not really a "prepared to surrender" situation. They knew that there were some on the Japanese Supreme War Council who were pitting their hopes on continued Soviet neutrality, and had recognized there was no possibility of Japan winning the war, but even they were still a long way from an unconditional surrender, and possibly a distance from a conditional one as well.

If anything, the end of the war in early August 1945 came as a surprise to the military and intelligence analysts, and the US found it somewhat difficult to immediately pivot its approach to Japan.

So why would anyone claim the contrary? After the war, there were several high-ranking US military leaders, notably General Eisenhower and Admiral Leahy, who said that they thought the atomic bombs were unnecessary and that Japan was likely to surrender without them. And after the war, the US Strategic Bombing Survey concluded that the war would likely ended prior to a US invasion date (November 1945) even without the atomic bombs, even without the Soviet Union's declaration of war against them, and even without a threatened US invasion.

Why all these changes in views? Some of this was partially an honest assessment of things, to be sure — Japan was, it became clear, in a bad place, even without all of the things that happened to it, certainly with atomic bombs plus the Soviet occupation of Manchuria cutting it off from its resources and threatening a two-front invasion.

But a lot of this also reflects military politics of the late 1940s. Prior to the outbreak of the Korean War the US military was afraid that Truman would use the apparent success of the atomic bomb as an excuse to cut military funding dramatically. And this is in fact what Truman was interested in doing. The military figures pushing against the idea of the atomic bomb being necessary were saying, in essence, that the war had been won not by the atomic bombs, but by the strategic bombing campaigns that predated it — and that only the threat of "boots on the ground" would really compel an enemy to surrender. No boots, no victory: you need a large military for this approach, unlike the "atomic diplomacy" approach.

By 1950 it became clear that the US approach was going to be having a large conventional military and have lots of nuclear weapons, and the military made their peace with them. But there was an intervening period in which military brass conventional wisdom involved poo-pooing the role of the atomic bombs, and that is the sort of quote-fodder that makes someone capable of finding US military and intelligence officials who later said that they thought the bombs were not necessary.

But there is no evidence that they voiced such opinions before the end of the war. Maybe a few of them harbored such thoughts. It's always possible. But it strikes me as more likely that they did not know what the future would bring. Nobody at that time was clairvoyant, and even the people planning to use the atomic bombs did not think that two of them would lead to a swift end of the war. (General Groves, the head of the atomic bomb project and always the strongest advocate for their use, thought it would require more like five of them. This is partially what I mean by it being something of a surprise.)

I want to make clear that just because the military brass had reasons to dislike crediting the atomic bombs with ending the war does not imply the opposite (that the atomic bombs did end the war) is true. The people who argued the latter had their own reasons for doing so as well. All people have reasons for arguing what they argue. The study of history is not about finding a "bias" and suddenly proclaiming the opposite to be true. The end of World War II was a very complex event and historians are still arbitrating the role of the atomic bombs versus the other factors. It is not a simple thing.

A nice overview of the claims and their issues is: Barton J. Bernstein, "Ike and Hiroshima: Did he oppose it?," Journal of Strategic Studies 10, no. 3 (1987), 377-389. On the complexity of factors leading to the end of the war, I always recommend Tsuyoshi Hasegawa, Racing the Enemy, as it does a very good job of laying out the various perspectives about this.