A couple years ago my mom came into possession of a Curta.

The weird thing: Is has no serial number. Not on the bottom plate, or inside.

I've looked around and can't find any real mention about devices without a serial number. The only one being a short mention about it bein a demo device, but I can't really find any source for that claim.

Other idea would be that it is a fake. if it was, it would be quite a good one.


Does anyone here have an idea what could be the cause?

https://imgur.com/a/3fQ1Wwo

As I suspect, there are two possibilities:
As an internal experimental unit of Contina AG - or as in your case: a Curta from the very last production series,
or (most likely) even after the closure of the Contina/Hilti factory - made from leftover Curta parts - 1971 or later.



Here is a "numberless" Curta Type 1 from a Contina engineer that was used as a test unit, produced in November 1954/January 1956.