Theories and Confirmations...
Well, we've known about this for about a year and now we have rock solid proof. Before seeing this, there was perhaps a small amount of doubt in my mind... but that's gone now.
Seeing as how Mutt says to Indy early in the film,
"Mutt's the name I picked. You have a problem with it?" I can see him embracing the name "Henry Jones III" at the end of the film to complete his story arc. He begins the film rebellious and antagonistic toward Indy (mostly his academic life, until he sees Indy in action), then at the end of the film he's out of his leather jacket and jeans and in a suit and tie with Oxley and his mom at the ceremony where his dad is named Associate Dean (or perhaps Dean) at Marshall College. (As I think we caught a glimpse of in the
"That's A Wrap!" video.)
That's how I would write it anyway. A wedding scene seems too on the nose... as if from a lesser film... and not truly in keeping with Marion and Indy's on-again, off-again, tumultuous relationship. I wouldn't marry them on the page if I were Koepp. Give Indy a son, fine... but don't domesticate him!