Rut roh. OK, I better start checking around then. And looking for options. I guess I don't care all that much whether the brakes are original or not, just that they work and are safe. And hopefully not TOO costly.
The problem is the small bolt pattern with 10" was stopped in 1972. The small bolt 1973 to 1976 went back to 9". All disc brake A body cars from 1973 to 1976 were 10" but big bolt pattern.