I have a S&W 65-2 and a 64-4 that I am considering swapping the hammers and triggers mostly for cosmetic reasons. I want to clean one of them up to a nicer condition. The other will just be a beater. According to the S&W revolver parts list, these carry the same respective part numbers for both guns. My question is how much work is there to swapping out these parts. Are they drop-ins or would there be some smithing involved. I have totally disassembled and re-assembled my S&W revolvers before so that is not an issue. Just not sure what to do if some adjustments need to be made to the parts to make them work with mating parts.