It depends on the type of mount you want to use. The top mounted types, claw- and pivot mounts as offered by EAW and Recknagel, even the clumsy Redfield type, fit the pre-war models as well. Minor fitting is sometimes necessary.The side mounts labeled "for Mannlicher – Schoenauer GK" or other post-1952 models like MC or MCA are not usable on earlier rifles. Most post-52 M-Sch rifles have a factory cut in the left side of receiver and magazine. These cuts are filled with a blind plate inside the stock. For mounting a side mount this plate is removed and the flat mount base plate installed instead. As the pre-war M-Sch are not milled for such a plate, you have to use a side mount for a small ring Mauser, modify it slightly and screw it to the receiver wall. All scope mounts on pre-war Mannlichers have to be quite high to clear the bolt and safety lift.