That water damage could be fixed if I'm not mistaken, but it would cost money. If this thing is quite valuable, it would probably be worth it to take it to a conservator. If its not, then at least like D&B said, it's not affecting the print itself.
Those stains in the margins are quite common in old prints. It sort of begs the question, how do these framed prints get water on them anyway?! I've just got an old drafty house myself, but it's always managed to keep all of my stuff dry