The posotion of the case screws in the open face movements was changed somewhere between serial run 14101601-14101700 and 14126601-14127500. Below you can see a photo from each of these runs and the change in position of the screws. Although the position of both screws was changed, it is easier to refer to the variations by saying that in the first variation, the case screw is found on the barrel bridge between the crown wheel and the ratchet wheel. In the second variation, the case screw is positioned at the end of the barrel bridge.