nah they didnt try to make it a comeback or say he was young
the whole premise of the movie is rocky is getting older and he feels like life is passing him by, the only great thing he did was when he was younger, kinda like a midlife crisis thing
they played to the fact that he was old in the movie, it really works well
there have been lots of real boxers who have came out of retirement when they were older for a few more fights