Dents can be removed, I don't know about bulges. Simmons charges minimum $75 per dent.
Your friend was cheated. The gun is not "real old" unless he is very young and considers 40 as old. It is not "worth a lot of money", bolt action shotguns are pretty much the bottom of the barrel.
Why do people pay good money for stuff they do not understand?
The internet makes research BEFORE the deal easy and a lot more useful than the posts "What did I just buy?" or "Did I get a good deal?"