I have an early 721 in 30/06 with recoil pad. Looking for early 1948 butt plate. Were they all aluminum? Checkered or serrated? When did they change styles? Were they all curved?
I have several Remington 721's and 722's. My earliest with the original butt plate was made in 1950 (I have one made in 6-48 but the plate has been replaced with a pad) and the latest was made in 1961. All the plates on mine are aluminum, checkered, curved, and are stamped "Remington" horizontally. In looking at old catalogs, the pictures show curved butts and the description reads, "Shotgun style metal butt plate, checkered to prevent slipping." FWIW: My 725 has the same butt plate as the 721. I believe the same butt plate was used throughout 721,722, and 725 production until they were discontinued Dec., 1961 (with the exception of the .300 H&H and, in the 725, the 375 H&H and the .458 Winchester Magnum which were fitted with recoil pads.)
A very good picture of a typical Remington 721, 722, 725 butt plate can be viewed on the auction side; #950891332, picture #3.
FYI: Numrich lists the old style aluminum buttplate as being the same part# (779420A) for all 3 models but is out of stock.