The hammer to spring strut junction was changed from ball/socket to the stirrup (fork)/pin in c. 1962 for all J frames (Model 36 Chiefs Spl. at ~ #295,000) thru 1997-8 and continued when the firing pin was removed from the hammer nose and mounted in the frame; Kit Gun rim fire hammers thru discontinuance in 1991.
If you can only find the later style hammer, just replace your spring strut rod with later style with the fork in the upped end, they're cheap. Either of the forked struts, 1st or 2nd version will work.
Ball tipped spring/strut assembly:
Photo credit: Gunparts
Available here for $6.00:
Smith & Wesson Model 32 Parts | Numrich Gun Parts
The hammer to spring strut junction changed from ball/socket to the stirrup (fork)/pin c. 1962.
Early forked 'Mainspring stirrup' was a round rod. Later flat rod is just called a 'stirrup' in 1977 parts list (shown w/o spring & retainer):
Hammer with pin at bottom edge for stirrup spring strut:
Photo credit: Gunparts
1st version rod stirrup spring strut assembly:
Photo credit: Gunparts
2nd version flat stamped stirrup spring strut:
Photo credit: Gunparts
