Factory refinish is always preferable over aftermarket.
Bear in mind that Colt outsources their nickel plating, but all prep and polishing and blueing and case hardening is done at the Factory.Colt used to mark the frame on a factory refinished gun but i am not sure they do that any longer, which was a nice touch and provides collector provenance to the fact that the gun was factory Refinished. Even a Colt Archival Letter won't necessarily(in fact, rarely if ever do) state if a gun was refinished. On a gun such as you described, refinishing will not materially affect the value.
All depends on the gun
An 1875 Peacemaker, as an example, in original, functioning,unmessed with condition, should never see a refinisher(or a bath!), but that's a whole different realm of gun collecting when you get into true antiques and historic arms.
Personally, I think that restoring classic, older arms(not speaking of true collectibles like antique SAA's,etc) is a very good thing as it helps keep more specimens of a particular model functioning and intact and helps preserve our firearms history by keeping classic guns out of the trash bin!