Kriegsmarine Identification Unit stamp on KM Clocks, why not other items?

[2dresq]

Greetings,

I guess seeing a recent posting of a KM Ship bulkhead clock got me thinking about ths.

Now, we have all seen examples where there would be the mark "N" or "O" and then there would follow numbers signifying the unit.

Question #1: What was the designator and what was the guide to assign a specific command or unit, a serial number?

Is there a database to show what kind of unit a certain piece could be attached to?

Question #2: Pocket Watches, Bulkhead Clocks were marked, Why not expensive portible navigation items such as Sextant, or other various tools with this unit identifier placed on the item?

If anyone has some insight on why this was that timepieces seem to be the only thing that was identified in this way; I would appreciate any thoughts or wisdom in this.

Regards,

JustinG

2dresq