David,
Somewhere through the WWI run...maybe 1916 or so...Erfurt (I think your luger is an Erfurt...with the proof marks shown in your photos...) started milling the receiver "notch" into all of their receivers...regardless if the pistol was to be a P-08 (4") or a LP-08 (8"). Just because your luger has the notch does not necessarily prove it was a LP-08 converted to a short barreled version...
Can you post a close-up photo of the "witness marks" underneath the bottom of your receiver...where the barrel screws into the receiver ? Take your barrel/receiver off the frame before taking the photo. This might yield a clue if your gun was rebarreled or not.
p.s. I missed your posting from a few months back, sorry...I live in the East Bay. LF member, Doc Fisher, lives in the Bay Area as well. We get together from time to time, as our work schedules allow. Drop me an email at "pebbink@pacbell.net" if you would like to catch up with us during our next luger outing...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />