None are interchangeable. Contact Numrich Gun /Parts Corporation www.gunpartscorp.c
Try Numrich gun parts corp.go to there web sight and then look up the model you are interested in,they should have a exploded view of your Smith and wesson.
Gun shop, gun shows, want ads, e-gunparts.com
Many are
Contact actionsportgames of Denmark thru their website.
Contact S&W
Numrich Gun parts Co. www.e-gunparts.com/ Search for Smith and Wesson 32
Try nurmich arms
Try e-gunparts.com
My 32 long ctg revolver with serial number 29223 was made in 1904. I talked to Roy with smith and Wesson and he told me it would've left the factory in May of 1904. I'm actually awaitting the papers for it now. Its a beautiful gun and it still fires, although i won't be firing it. It has genuine mother of pearl grips, and all original parts. I should have asked him exactly how much its worth.
Gun Parts Corporation (AKA Numrich) is the source for replacement parts for most obsolete firearms http://www.e-gunparts.com/productschem.asp?chrMasterModel=1980z66 they list all the standard Model 66 barrel lengths
You can find a parts diagram for a Smith & Wesson 5-shot .38 J-frame revolver on the manufacturer's official website or by contacting their customer service. Alternatively, you may find aftermarket parts diagrams on online gun forums or websites specializing in gun parts and accessories.