Hello Bob,
Regarding the "S" on the receiver you mentioned...can you describe the shape of the "S" in a bit more detail.
Is the "S" a rounded symbol or is it more flatten along its sided and taller that it is wider ? This info. might help us decide if your receiver is a Simpson-Suhl luger or an S-code HK luger...
The finish on your 1939 dated pistol might just be regular steel that was polished before a refinish that never occurred (i.e. left "in the white"...). An other possibility would be that your 1939 was assembled from left-over parts in the gun factory at the end of the war, from un-finished (un-blued) parts by factory workers for the liberating soldiers...(just WAG's on my part...).
I suspect if truly a zinc-alloy gun, your 1930 gun/frame would be considerably lighter in weight that your other luger. You might want to compare the two on a kitchen scale...
As Ed mentioned, photos would be of trememdous help.
p.s. The WWII guns that are commonly described by collectors as the "Black Widow" were a 9 mm. pistol used by the German forces and would normally have "byf" on the its front toggle link. If yours is .30 cal. and has "DWM" on its toggle link, it is probably not a real BW luger, but another variety that someone added the BW grips to, somewhere along the way...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />