Hello, lonegunman. I seem to remember that the M/S housings could be just as readily replaced in the the full size framed 1911s by Springfield as in any other 1911, but that such was not the case in whatever they call their small, compact 1911 as the retaining pin hole is not positioned the same...or something similar. Could be wrong, but seems like everyone thought SA had changed the hole position in ALL their 1911s so that replacing them with non-locking, traditional housings would be more difficult and this turned out not to be true...except for the little gun.
Best.