IIRC, Rory turned pro as a lightweight at 16.
He didn't move up to 170 until he was something like 17-18.
I don't know that his extreme size and weight gain occurred as a result of steroids... Maybe it happened because he was still growing?
The HELL you say?
People don't grow between 18-23, especially if training with one of the best camps in the world. They simply gain a couple pounds because young athletes in growing bodies are very limited to the amount of size they can gain.