Anyone have a source for out of stock parts?

I am looking for a few parts for a 1998-era Nikkor AiS ED 600mm f/4 IF lens. So far all the big repair shops have told me that the parts are out of stock and no longer available from Nikon (at least not in the US). I am hoping that someone might know a source for out of stock parts. Even used parts stripped out of a damaged lens would be OK.

The parts are related to the lens mount and are involved with stopping the lens down. It functions perfectly wide open but I am not able to stop it down without:

Blade actuating ring Part # 1b574-029-1
Block Part # 1k680-037

Block Part # 1k680-036-1 (found this one but included just so you can see what others in involved in the repair)

I would be happy to pay a finders fee to anyone who can help me locate these parts. Thanks in advance for your help!