Sources for 89 prototype rims

[Sphinx]

I'm starting a patient, 6 month, search for the right zr1 for me. I've always had a soft spot for the 90 saw blades and the 89 prototype rims. If I buy a non-90, are there any aftermarket sources for 89 or 90's rears? Correct me if I'm wrong but the front ones are interchangeable with the non zr-1's of the same vintage.