I have an American Futurematic with a snap-on back and a Swiss one with a screw back. Would the movements in both of them be the same?
Also, I recall you saying not to try to wind the watch beyond the quarter-to point but my Swiss one winds easily up to ten-to. I'm careful not to do this since reading your post but would be interested in your comment here. It runs perfectly.
If the displays both have needles for the seconds and power reserve then they would have the same caliber 497. 10 till is still OK, but I would but advise going beyond that.