I find it amazing Rokinon will service their old stuff from the 80's.......that's a company that really stands behind their product if that's true. I've got an old 80-200 f4.5 and a 28 2.8 Rokie and I love them.

I work as a repair tech in a laptop repair center and have a fairly large box of screws. Send me a photo of what you need and I'll dig around at the office tomorrow to see if I have it.