Well, a very similar stamp was used for centuries as a symbol for the town Suhl. Here is a scan from Gargela & Faktor, "Zeichen auf Handfeuerwaffen".

On the Schmidt & Habermann Drilling it is in the same inconspicuous place, the breechface, as the "Made in Prussia" stamp on fi the Lindner-Daly shotguns. H.A.Lindner is a famous Suhl "gunmaker", but famous only in America as he appears as the "maker" on some of the finest s/s shotguns imported pre-WW1 by Charles Daly. In Germany he is completely unknown, not a single gun bearing his mark has ever surfaced in Germany. Apparently he was merely a "Rucksackbuechsenmacher", as such men were called in Suhl, merely an agent who ordered work from the Suhl craftsmen and carried parts from barrelmaker to actioner to stocker to finisher..and so on in a Rucksack. Of course Lindner was not interested in letting Daly know who actually made the HAL marked guns. So I believe most of those "Suhl" or "Prussia" stamps were not applied by the makers, but by dealers ore other middlemen.