Recent Find

[Dieter3]

I just received a 1931-1934 Manchuria medal, really an excellent condition specimen. I was only after the medal, not as concerned with the case. I did know there was a case to go with it but that it was in pretty bad shape. When I received it, I was actually pleasantly surprised at the level of damage (yes, I know that sounds odd!). All of the pieces of the case are present, but the interior panel of the lid was no longer attached, but this revealed a character and number, ハ67.

I'd imagine a lot of experienced collectors have seen such things. Is this some sort of numbering or serializing scheme to the cases? Anybody know what other pieces may bear markings?