They will interchange in some cases. If you look in S&W's revolver parts list PDF you'll see that hammer #293660000 is listed for the M10, M65, M66, M67, M386, M586, M686, M696, M617, and many others.
I suspect that this particular hammer is common to all of the models that feature a frame mounted firing pin. Unfortunately, the parts listing does not list revision compatability, so that's only an assumption. BTW, under revision all the different models that list this hammer has the revision marked as 0. Another assumption here, that revision 0 is the level for the hammer, NOT the gun it's used on.
One of these days I plan on pulling the hammer from my 617 and trying it in my 620 just to confirm it works. However, since Brownell's doesn't seem to carry this particular part number I not in any great hurry to do that.
BTW, anyone with a 6 inch, frame mounted firing pin, 686 equipped with the .500 target hammer, please post the dash number of your gun. I've got an itch to set my 620 up with the wide hammer and .400 smooth trigger so it matches my 610 and the way that Brownell's is set up knowing that dash numer is the only way to be sure I get the correct hammer and trigger.