I believe it depends on the year and style of brakes that are on the car. Just guessing based on your name but that would be a 1968 Mustang? If I remember correctly, the rotor and hub are 1 piece. In that case, you will find the answer to your question is based on the rotor you buy. I think you can get rotors that have new racing in them already or rotors with no races installed. That info should be available before you purchase. If you get rotors with new races, throw some new bearings in as well. If your bearings are in good shape and you get rotors without races, go ahead and reuse them, just make sure to repack them and set the backlash properly.