i wouldn't say he is definitely on.
i have been around 6-8% at 164 @ 5'10 after 2 years of working out, and i have horrible genetics. the only thing i used was ripped fuel (ephedrea, this is how long its been since i have been in any kind of shape).
but i am guessing that he is not on because he doesn't seem to be bigger than in the 170's, if he is much bigger than that than i would lean toward he is on something.