It does matter. The 70-72 B And E rotors are available. I have the Centrix versions from Rock Auto for the stock KH set up. These are solid versions. If you need the 2 piece unit for a show/points car, that has to be a used set. I do have a nice used pair if that is what your after. For a driver the centrix have worked very well for me and others I have seen post. Fit correct and come with the bearing seat installed.