Rear drum anchor pin nut

[old blue 1968]

I have a 67 C10 long box, its down to the frame, rear end is just about done, during disassemble, the achor pin nut was so rotted it jus broke off, its a circle with a notch cut out of it to keep it from turning, not many junk yards around here, and am trying to keep it as original as possible. Searched the net, not having much luck finding one like that, any help would be greatly appreciated, Paul