Hey Yovis, I've spent a lot of time researching the Nabataens and I'll try to source what I say below.

I will be using Wikipedia as a source I'm afraid, I do have better sources but they're PDF's on a cloud so for ease of reference I'll be using mostly Wikipedia.

The Nabataens certainly match the description of an early Arab civilization, they seem to have been a nomadic tent dwelling people who settled in Edom and profited greatly off of trade between South Arabia and the Mediterranean world. The Nabataen state later encompassed parts of North Arabia, Negev and Southern Syria. According to Diodorus Siculus ^source they are Arabs and culturally conservative at that.

He says of the Arabs that:

"It is their custom neither to plant grain, set out any fruit-bearing tree, use wine, nor construct any house; and if anyone is found acting contrary to this, death is his penalty. They follow this custom because they believe that those who possess these things are, in order to retain the use of them, easily compelled by the powerful to do their bidding. Some of them raise camels, others sheep, pasturing them in the desert. While there are many Arabian tribes who use the desert as pasture, the Nabataeans far surpass the others in wealth although they are not much more than ten thousand in number;"

Despite this description we do see the Nabataens build grand structures in the rocks of Petra.

While Nabataeans originally spoke their own Arabian influenced dialect of Aramaic ^source the Arabic script itself is probably descended from the Cursive Nabataen Aramaic script ^source and the Nabataen Aramaic Namara inscriptions dated to the 4th century AD bear strong similarity to the classical Arabic spoken in Northern Arabia and Hejaz in the 6th century AD.

The Umm al-Jimal inscriptions are also an indicator that the inhabitants of the region were Arabs before the events of the 7th century.

Edit:

For more on the inscriptions I suggest you read this

For more on pre-Islamic Arabia I suggest you read Rome and the Arabs by Irfan Shahîd.

Alternative sources:

Ancient Arabia - A brief history and timeline

"New Nabataean inscriptions from Umm al-Jimāl"

Diodorus Siculus Book XIX

Strabo XVI.iv.26