I understand that there were special order MS rifles that have some variations in the stock. I have a 1903 that was made for a detachable comb/cheek piece and the butt is checkered in lieu on the normal steel butt plate.

I understand that many gun manufacturers sold their rifles and shotguns unmarked so the retailer could engrave their name and location and present that they were the manufacturer. If the retailer didn't engrave its name, the gun became a "guild" gun.