I get that the collector/historical value, and therefore monetary value, has been chopped, but given that the guy stated that he plans to keep it forever, the monetary value becomes irrelevant. At that point, why not make it as nice as you can for your own use and enjoyment, presuming you've got the skills and/or budget to do so?
Same thing applies to classic/collector cars, really. If you find a "survivor" with little to no rust, do you just fix what absolutely needs fixing and stick with the original paint, etc, or do you spend the time/effort/money to make it "perfect," including any mods you'd like to do? Well, that depends; if you plan to sell it or you just love having it be as original as possible, the answer is obviously the first one, but if you plan to keep and enjoy it, well, maybe it gets a ground-up restoration with new paint, upgrades/mods to your taste, the whole 9 yards. It's a personal choice, and of course some people will (violently) disagree with whatever you choose. I say pick the way you want it to be and ignore anyone who yells at you for it, be it a gun or a car.
