The most popular pad in the late teens, 1920s & 30s was the JOSTAM ANTI-FLINCH --
Jostam Anti-Flinch catalogue entry.jpg
unfortunately, the one popular period pad that hasn't been reproduced. It was the standard pad for the lower grade A.H. Fox guns, numerous J. Stevens models, etc. Finding a NOS JOSTAM ANTI-FLINCH is getting pretty tough!!
CSMC's repro No-Shoc is the large size with 3 1/4" hole spacing and will require quite a bit of grinding to fit an 0-frame stock.
Another choice would be JOSTAM HY-GUN. The patent covering its design was granted Sept. 20, 1927. The HY-GUN repro is also a large size and will require a lot of grinding.
Jostam Hy-Gun, American Rifleman September 1929.jpg