Probably. Some people seems to think his Philly shell stance is what makes him the best defensive boxer around, but he's just as good with his high guard. It's is ability to anticipate what's coming and roll with the punch/dodge that is the best. I also agree with the mental aspect answers. We hear Gayweather and things like that everywhere, but no matter who they put in front of him, he always ends up being the bully.
Have to say I was amazed at his corner after the second round of Mosley-Mayweather. You could just see the supreme confidence. Badly hurt and all they were thinking is dominate the rest of the fight, and he did.