Not to belabor the obvious, but some people don't know (especially TV writers and prop people): it has to be an auto pistol. You can't silence a revolver, generally speaking (I once read of a special run of Smith .38s with very tight cylinder gaps that were made for some government agency, just for that purpose).yes....almost anything can be fitted with a supressor.
#1 is a new longer barrel to be threaded, and then the supressor.
$ 200 one time transfer tax if legal in your state. figure 3 months to get approval after all paperwork is submitted.