Brian,
Welcome to the Luger Forum, congratulations on your first Luger purchase and thanks very much for showing it to us.
The unit mark on your gun is that of a medical trooper of a Bavarian military support column. There have been several discussions of this mark, if you go to this link
http://forum.lugerforum.com/showthre...light=bavarian you will find one here, althoug regrettably the pictures have expirerd.
There is another forum, Jan Still's Luger Forum, which also has discussino threads on these units, you can find them here:
http://luger.gunboards.com/topic.asp...Terms=bavarian
http://luger.gunboards.com/topic.asp...Terms=bavarian
http://luger.gunboards.com/topic.asp...Terms=bavarian
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The posts include a small database of these Bavarian unit marks; I've added yours.
--Dwight