I'm confident Billy is capable of achieving whatever he was purported to have cheated.
He's pretty good, and has done some nice runs in public, but running MAME and claiming not to be is a problem. There was earlier beef about playing on the wrong board, which is less problematic, but at the same time --- rules are rules, and learning enough to inspect your machine isn't too hard, IMHO. It should be real easy to see if your machine is a computer or a 1980s crazy circuit board; but the earlier issue was more subtle.