This is the one that started it all, a Gruen Precision Autowind. It was a gift from the woman that I eventually married. I received it new in 1969. I recently took it out of the safe to wear on our 39th anniversary and noticed one of the black inserts on a number marker had come loose. My Problem: I can't figure out how to open the case in order to fix the marker. The only markings on the case back are the words GRUEN and 14k. What appears to be a seam in the below photo, isn't.
Thanks in advance for any suggestions.