Hello all, I have two Mamiya 6MF cameras and have discovered an odd difference between them that I cannot explain. I am hoping the group may help me find the answer. One of my 6MF cameras has a rewind button on the base plate, near the battery compartment. The other 6MF does not have this rewind button, but rather a flat metal cover that cannot be pressed. This is important to me because I use the panoramic adapter, and the camera without the rewind button will not allow me to rewind the film once I reach the end of a roll. Has anyone had this issue before? Does your 6MF have rewind button, or not? Thanks for any advice you can provide. - Jeff P.S. Both cameras are in the 315XXX serial number range, and it appears they were built about 1000 units apart.