I originally posted this in Clocks but got no input. Pocket watches seems inappropriate and since people who collect chronometers tend to be interested in history.... I acquired a transparent celluloid cased 37500. You can see it on my website at: http://www.historictimekeepers.com/preproduction_display_cased_3750.htm Sadly, the celluloid dial had shrunk and actually pulled away from the mounting screws, it crumbled in my hands. So, I skeletonized a NOS dial. New Stainless springs as well. Interestingly, the movement has no serial number and the same with the case although it is molded just like the bakelite cases. I thought I had seen one of these before, but I am not sure if I am "recovering" a false memory. The seller was adamant that this was a pre-production model used for the final contract approval process. I am inclined to believe this is possible given that the usual serial number on the top plate is missing. Can anyone shed light on this? The only thing similar I ever saw was a photo where someone milled off the back and fitted a Plexiglas plate in its place. This is a factory injection molded case that is from the same mold used to make the Elgin Bakelite cases.