it is my own personal opinion that he always did believe he was a natural.
hgh is something the body produced naturally. So the heavy use of it - down the point where one leg was rapidly outgrowing the other on him - coudl still be considered (by him) to be natural.
he used to offer to take polygraphs, etc, didn't he? Dude was LOUD about him being a natural. I dont think he really belived he was anythign but giving his body what it already had naturally.
He even TURNED DOWN a PRO CARD, because he wanted to win it again, right? It probably had nothing to do with taking any test.