Not sure I'm correct but here goes anyway. To install the Galloway short trigger parts you have to remove the body (Plastic) from the frame (steel). That requires removing the roll pins etc. Again not knowing how it is put together I'm guessing that that leaves you with a plastic housing to fit over a steel frame. If roll pin holes are in the same location I would think that the two would interchange, but as you said will S&W sell only the plastic frames. In the case of KelTek they sell different color housings so you could change the color daily if it suited you and the only thing KT wants is your money. . Just some random thoughts and possibly not correct. If anyone finds out please post it here.