RevDocDrew,
Great picture trail on the recoil pads. I'd suggest a correction, on the Ithaca "bridge trestle" pads. As introduced circa 1931/1932 they had a black hard rubber base.
The original run had PAT. APPL'D FOR under the ITHACA GUN Co. ITHACA, N.Y. logo.
Eventually this was changed to PATENTED.
The Aluminium base first appears in the Summer 1950 illustrated Ithaca price list --
The Aluminum base pad is still offered thru 1953. I then have a ten year gap in my Ithaca paper and by 1963 they are offering this pad --