Just to clarify what Hitzy said - because people manage to screw this up too - the threads that attach the bushings to the frame are different, the threads that attach the grips to the bushings are the same - ie, if you want to replace your grip screws with aftermarket allen head socket style grip screws (AKA Hex Head) you're fine. If you want to run slim grips, you'll need to work the bushings.