Miracles never cease... wikipeedia actually managed to get something right.
Yes the 147 is a waffenamt, and it is for Döbeln; but WaA147 is an inspector, not a firm, and most things made by Grossfuss (bpr) & H.W. Schmidt, Metallwarenfabrik (brg) were inspected by WaA497, or actually under his authority. WaA147 is a rarely seen inspector for Döbeln, mostly found on Grossfuss MG components, and even then rarely. WaA147 is known outside of Döbeln also, like nearby Freiberg, but as in this case sometimes on brg buttplates. BUT, this has no relationship between Grossfuss and Schmidt, they were independent firms and both metal workers (stamping).
Oh, and waffenamts represent the military, not factories, they cover areas, or sometimes very large and busy firms.