Unfortunately the friend I bought my DH 28 gauge from replaced the pad prior to my purchase. Letter documents the Huntley pad. I have attached a link to a drawing on the patent. I am currently debating about either a leather covered pad or installing a Jostam sponge rubber pad.
My gun was ordered in 1916 by the Charles Parker co NYC for E H Hotchkiss ( Stapler company) cost of the pad was $4.00
https://patentimages.storage.googlea...S1222291-0.png