SM, in the day these guns were made, guns were made by the village/town gunmaker, of course. If you had the money and wanted a gun that is where you went. Everyone within his sales area knew him and knew his products. Signing would have been superfluis and ostentatious. I doubt that he ever considered that someday somebody in USA would wonder at his work; quite beyond his imigination. The norms for distribution of goods was vastly different from today. Hard for us to imagine he wouldn't sign his work and equally hard for him to imagine craftsmen of his skill level now vieing for global distribution.
