The 15 has adjustable sights, the 82 doesn't. I see duplication only in cartridge chambering. I have lots of cartridge duplication and 2 of exactly those you mention. The revolvers are quite different and you can't have too many.
I've ended up with more .38 Specials than I thought I would. For some reason, I don't have a problem with .38 Special redundancy.The 15 has adjustable sights, the 82 doesn't. I see duplication only in cartridge chambering. I have lots of cartridge duplication and 2 of exactly those you mention. The revolvers are quite different and you can't have too many.