The Oxyrhynchus Thomas fragments are dated to 130-250 B.C., not to the time of Christ. As I said, I've never heard anyone argue that Thomas was written while Christ was still alive - my understanding is that the American guys who date it to 40 put it the earliest of anybody. And even they trace it to a pre-existing oral tradition (although some believe part of it came from Q1 and Q2).
The only people I have seen give early date to Thomas are Crossan and the Jesus Seminar lunatics.