Hello Noel,
On page 270 in Jan Still's book, "Weimar & Early Nazi Lugers", he shows a good photo of one nice 1920 Commercial (which he calls Alphabet DWM lugers).
It has a blank chamber, vertical C/N proof, has a 4-digit + suffix serial, and does not show any military-style number stampings.
Let me know if you have this book or not. If no, I would be glad to mail you relevant pages...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />