I could be wrong as I do not own a Glock at all, let alone both of those you are asking about, but I remember reading that at least for the compact models the ones chambered in .40 and .357 have a couple metal bits in the frame that the 9mm models do not have. Meaning you could put a 9mm slide on any of the frames, and you could put a .357 on a .40 frame or vice versa, but it isn't a good idea to put a .357 or .40 upper on the 9mm frame.