9mm Para., 4 basic variations - only the first 2 types have the more desirable shoulder stock lug. Military pistols are usually "SA" marked, approx. 9,100 mfg. 1938-1954.
the shoulder stock for this model (w/o serial numbers) features a sheet metal compartment which contains a cleaning rod and extra magazine. Original stocks (only 50 mfg.) are currently selling in the $6,000 range, while more recently manufactured stocks utilizing original hardware are currently priced in the $2,500 range.