I have a 79’ … rotor bolts to the hub after the wheel lugs are pressed in.
these from Cruiser were the replacement… Brake Rotor - Fits 9/1975 - 7/1980 4x/5x Series - https://cruiserteq.com/brake-rotor-fits-9-1975-7-1980-4x-5x-series/
going to get the backing plate eliminator next time I dig...