Each gun is separately fit to the case, so any - any - dimensional differences would make it impossible to switch the position of the guns. Even something such as the positioning of the forged front sight base, or the O.D. of the barrel, would be enough to prevent switching.

To my eye, the Ropers are the same size. One of the two guns is a zero-gun, the .38 as I recall, and it is a few years earlier than the K-22 2nd Model. There could be subtle differences in the dimensions of the grip frame.

Mike Priwer