Olypenn22:
Please post some pics and Carl Bock was the firearms merchant who may have been the wholesaler who sourced the components and then subcontracted the work to Kessler who roll stamped his name atop the top rib. GGCA( www.germanguns.com ) has F.W. Kessler catalogues forsale with the copies being from an example I possess. First I'd say the serial number was in the Sauer range but the dreiling would be an early one so I'd say Kessler made it in his shop in Suhl.

Kind Regards,

Raimey
rse