I don't have a clue so probably shouldn't even post this but it is my understanding (possibly 100% wrong) that all late model Ferd wheels are metric-sized which makes them rare birds not interchangeable. i also believe that all GM and Dodge wheels are SAE and interchangeable bolt pattern but maybe not the same backset. I believe that most 3/4 ton or one ton srw (not dually Budd wheels) GM/Dodge/trailer wheels are interchangeable.
Please, someone correct me if I am wrong and I'll learn something.
Oops! Myi apologies. After posting this I realized you were asking about 3500# axle wheels, not the larger ones. I know in the back of my memory that you haul commercially so I was thinking heavy trailer, heavy wheels.
3500# trailers us a wheel that has the same bolt pattern as a 1/2 ton GM/Dodge pickup wheel, I think, but most don't have the same backset.
SouthWest Wheel is a good source of inexpensive wheels.