Bushing Size Question

[Duel72]

What I have is a '72 C-20 Longbed Dually with leaf springs and a Dana 60 rear axle. This seems to be an odd ball set up like the factory grafted a C-30 rear to a C-20 frame. Anyway, I was wondering if the spring eyes, shackles, and hanger bushings are the same as the regular C-20's or K-20 blazers or some crazy odd ball bushing that I won't be able to find. Your input is greatly needed. Thanks!