What sort of gun are we talking about? A big name antique is better left as is if there is any original finish remaining at all. As the long time collector told me, 100% reblue = 0% original finish. Most collectors dislike any form of refinish.
True restoration is very gradually getting to be accepted to some degree. Doug Turnbull, one of the best and best known, said he took a well worn Winchester worth about $2000 and made it look like new, whereupon it sold for $9000. But if it had been in truly excellent original condition, it would have been worth $15,000.
Something common and of recent manufacture, I think is ok to pretty up if you want to.
Be advised that "restoration" and "rebluing" are not the same thing. You do not likely get a gun restored by the guy with a buffer and bluing tank behind the hardware store.