Serial number and/or initials stamped in Swiss holster

[Empereur]

Hello all,

Is it common to find the serial number of a Swiss Luger stamped in ink in its holster? And how often do you find some initials stamped in the same manner (I assume it are the initials from the soldier who carried the Luger)?

I ask this because I saw them stamped in a holster for a M1900.

Thanks in advance,