Finally did something I've been meaning to do for a while and bought a micrometer. It looks to be pretty old, and I am definitely going to be reading that instruction booklet that came with it. I think I did pretty good for $32 on fleabay. Should be here Saturday.
I'm kind of amazed that the original owner kept EVERYTHING. From what I could find online, I believe that box design is from the 1920s-1930s.