i believe there is a gemara that deals with that issue, of whether moshe recived all 613 mitzvos with the entire torah as we know it, or he received it part by part as time went on.
Yes, it’s a machlokes in the gemara.
However, I don’t see how it’s possible to say that Moshe received the entire Torah in it’s final form at Sinai. After all, consider the following:
It says in B’Shalach that the B’nei Yisroel ate the manna for forty years until they entered Eretz Canaan. If this verse appeared as such at Sinai, wouldn’t someone have asked “Hey, what do you mean we’re going to be in the wilderness for forty years?”
If the Torah was given to Moshe in its final form at Sinai, why would Moshe hit the rock when he knew in advance that it would cause him to not enter Eretz Yisroel?
If the Torah was given in its final form to Moshe at Sinai, would Korach have rebelled knowing the fate that he was in for? Would the spies have brought back their report, knowing in advance the grim consequences? Would Zimri have committed his act, knowing that Pinchas was waiting in the crowd with his spear? Would Aharon’s two sons have done what they did, knowing that it would have cost them their lives?
If the Torah was given at Sinai in its final form, why would Moshe need to bring the question of Tzelaphchad’s daughters to HaShem? He already had the answer. Likewise, why would there be any doubt about the form of death penalty for the wood-gatherer? When the people who were tamei on Pesach wanted an opportunity to bring the Korban Pesach, why did Moshe tell them to wait for HaShem to answer them?
From these questions, it is very clear that the Torah was not given in its final form at Sinai. The text of the Torah could only have been finalized at the end of the forty years.
The Wolf