Dado, we have similar trucks as mine's a '62 C30. When I picked mine up a few years ago it had later model one piece rims on the front but still had the lock ring rims in back. I needed new tires in back and the tire shop found one of the rims and lock ring had rusted real bad and was too pitted to safely use so I bought another pair of later model rims for the outside wheels. I kept the lock ring rims for the inside wheels. The tire guys weren't crazy about working on those older rims and inflated the new tires in a cage as a safety precaution.
So be careful, you may have a rusted out rim that isn't obvious at first.
