I read online that the scenes that showed during credit were different on different cuts of the movie. (Dumb in my opinion.) I really didn't care for the movie. To many other mutants to be his ORIGIN Story. It would have been a bit more interesting to show some of the wars instead.
ON a side note I was VERY disapointed about GAMBIT the accent was there for him to say hi and then gone. The powers weren't quite the same as the comics either.