1970 Rupp Roadster Brake Backing Plate

I'm attempting to source a brake backing plate for a 1970 Rupp Roadster( part# 15278, #7 on parts list). I currently have one that has a seized actuator cam(part # 13782, part #9 on parts list), but I cannot figure out how to knock out the pin without destroying the entire backing plate. The replacement backing plate does not have to be in perfect condition, but just in working order. It does not have to be the entire brake assembly(actuator cam, brake arm, springs, etc.), since I can get any missing parts from blackwidowmotorsports.com, although they do not have the actual backing plate listed as in-stock on their website(figures!). If anyone is also aware of any other brake assembly that might work on a 1970 Roadster, that would work as well!
Thanks in advance for any help!