Welcome to the THR Forum, Wilson. There might be a nice member on this board with parts. Try the Shotgun section, the Gunsmithing section, and the Trading Post section.
I get nearly all my old Remington shotgun parts on Gunbroker. There are also a half dozen other sources of old parts like Numrich and Sarco, but they are spotty at best. I get the best deals on GB.
Best of luck. Hope you stick around.