I remember speaking to a guy that trained at Gold's regularly, and he told me O'Hearn was one of the strongest guys there.
Interestingly enough, this same guy actually believed that O'Hearn was natural, as O'Hearn apparently looks great year round, and has never looked bloated, never gained a ton of weight, and has never lost weight.
Dude that I know has been around the game a long time, and if it weren't him telling me this, I would question his natural status.
Who knows though? I don't care either way. Obviously, O'Hearn has trained and dieted consistently for years now.