Very unlikely, as the German law clearly prescribes these markings: Maker, cartridge name, serial number. Then the proofhouse has to add these three markings: eagle/N for nitro proof, proofhouse identification mark and proof date. Usually you find these marks on the barrel flats under the barrels. Of course, you have to take the barrels off the action. Please, post a photo of the "sparse modern nitro proof marks".