Hello Mark,
From your description & based on the SN, your pistol seems like a Pre War Commercial. It should have a 5.5 in bbl, 7.63 mm Cal, 6 grooves rifling, 34 lines grips, fire blued small parts & should not have the New Safety ( NS ) stamped on the hammer's rear.
Of all the C96 variations produced, the Commercial 5.5 inch 7.63mm is the most common. A Pre War is always more desirable than a Wartime gun......and they are GREAT pistols !!
Any photos ??
MARK