My best guess is that the Jewish firearms merchant who retailed this met his fate at the concentration camps. It is possible there are multiple Arnot Adler of Prbram, but I've seen one listed as being born in 11.25.1888 & last known position was Prbram, then Praze, then Terezin & on to Auschwitz on 9.04.1942.

Transport Bd, ;. 742 (04.09.1942 Prague -> Terezn)
Transport Em, ;. 647 (01.10.1944 Terezn -> Auschwitz)

I'm fairly confident this is our Arnot Adler of Prbram.

Kind Regards,

Raimey
rse