I can see Pac getting a stoppage win (more like a ****-this-what's-the-point stoppage), but not a straight-up KO (10 count or sparkage). Mosley was accumulating HAYMAKERS on Margarito and Margarito was going down, but not lights out. That fight was actually a testament to Margarito's ridiculous chin (and nothing else, because Margarito had nothing going for him other than that ability to take shots to the chin forever), and I wouldn't say it's badly cracked as many people make it out to be.
Remember, the punch that set Margo down the road to KOville from mosley was a converted southpaw straight left. But I still can't see Pac knocking Margo out.
This would imply that he knew about the wraps though, and that he possibly knew he could be banned. If he is telling the truth, and he didn't know about the wraps...this wouldn't have effected him once that bell for the first round went.
I actually think he knew myself...but some people try have it both ways. They claim he didn't know about the wraps, but then claim the only reason Mosley beat him was because Margarito knew he was going to be banned. If he knew he was going to be banned, this implies that he knew about the wraps. It probably did effect him mentally, but not as much as people think in my opinion. All he knew was that it was being dealt with after the bout...
I think even he did not know, at the point he probably thinking to himself - "WTF - all these years I might not be as good as I really think I am. All those wins might be tainted". Self doubt can kill you.