Cotto didn't "luck out"; he just beat the guy. Margarito "lucked out" until the Mosley fight. In fights where we're certain he wasn't cheating, he's a very unimpressive 1-3. You can attribute the Cotto win to Margarito's decline, but in response to that:

1) You opined before the fight that Cotto had declined more than Margarito since their last fight; and
2) It's at the very least suspect that said decline coincides precisely with the discovery of the gloves at the Mosley fight.