sounds reasonable at first GodYankee...

, but why should he be younger only if he sais "Mr.Corleone" and shit... he could be just as old. the Hyman Zuchovsky actor looked younger than Robert DeNiro...that's all. no need for the two characters two differ a lot in age (but you could be wright, I guess all of you could, since Roth isn't in the DVD timeline, which seem to be quite official to the movie trilogy)