You could try Nicholson Hardware in Rockford IL. It is a 100 year old company that purchased much of the stock of Amerock when they closed. They have ancient stuff. I bet if you called them, or sent them pictures and dims, they will have it. They have two buildings next to the store that houses old stuff. They were able to find the mechanism for a 55 year old lazy-susan cabinet for me once. The guy said "I think those are in building 3". He was gone about 40 minutes and came back with a box that had 4 of them.
Nicholson Hardware
Address: 1131 2nd Ave, Rockford, IL 61104
Phone: (815) 963-4821
Hours: Open today · 7:30 am – 5:30 pm
Good luck!
Stan