Hi, these two dials have come into my possession via a good friend who won them in a recent watchmaker's estate auction. I am hoping a forum member can help me account for the differences on the back of the dials. As you can see, one has a number series while the other has a sterile back. Perhaps different factories or sterile back civilian dials? Any thoughts as to the differences? Any red flags as to authenticity if it is a sterile back?



