Do you know what he LIKES or WANTS, or are you just guessing or impressing what you like on him?
Buying a guy is a very personal thing for many reasons, and often people undersell the esthetics of it, as well as the ergonomics and other factors that go into this.
Not, mind you, that I'm against gifting a firearm to anybody "out of the blue". But this is something that you really ought to do the personal research into your own son to figure out rather than people like us.
Things to consider:
What has he shot before? Does he exhibit any preferences to style, caliber, design? Has he had his eye on something? What does he hunt? Is there a split between what he hunts and how often he hunts them to consider? (Such as small game, varmint, bigger game.) Does he target shoot a lot? Wood or synthetic? Single shot, bolt action, lever action, semi-auto? Detachable/non-detachable magazine, tube magazine? Blued or stainless? If he likes shooting a lot, can he afford to shoot what you're considering? What does he already have, if anything?
Honestly, all the input I can give you involves my own opinions based on what I like and what I might thing someone else ought to have. And since I don't know your son from Adam, that's a really poor basis to make such a decision on.