Compur serial number - non-standard

I have recently purchased a Balda Jubilette camera. The model dates from 1938. I wanted to use the shutter serial number to date the camera - it is a Compur shutter. The serial number is '0016596 - that apostrophe is a part of the serial number. I would expect a Compur shutter from this time to start with a 4 or a 5 and have seven digits. Can anyone tell me why the number is so strange? And can I still date it?

Problem solved - the '00 is the shutter size and the rest is a five digit serial number rather than the usual seven digit one. Apparently not so uncommon.