In the photograph on the left, arrow number one is pointing to the German military proof stamp that is located on the breechblock. This proof mark is also found on the barrel and the receiver as seen in the pictures above these. In the same picture on the left, arrow number 2 is pointing to the defaced serial number that is on the toggle pin. I believe this to be the work of the Russians when they rebuilt this pistol.
After very careful inspection, the entire toggle assembly minus the striker and toggle pin have matching numbers. As mentioned in the above text, the numbers have been scrubbed, and while difficult to distinguish, they do match the original serial number of the frame. Also correct for this Luger model is the extractor which is marked GELADEN on the left side.
While this Luger has a unique history, it is not original and pristine by any means. The photograph on the right is a picture of the bottom of the barrel with a stamp that no collector wants to see on a historic firearm that is in their collection. This is an importers stamp that is now required to be placed on firearms that have entered the U.S. after the late 1980's. On the plus side, every marking on a firearm will help to tell us its history and this importers mark is no different.
With this importers mark, we now know that this Luger which was probably captured and refinished by the Russians after WWII, came in to the U.S. some time after the late 1980's. The first line of this import stamp reads as follows, P08 9MM GERMANY, MFG and the line below it reads, C.I.A. ST. ALB. VT. This two line marking is exactly what the law calls for except it would have been nice if the importer would have hid this stamp under the grips rather then stamping it on the barrel. The first line of this stamp identifies the firearm and where it was made. The first line tells us that the model of the pistol is P08, the caliber is 9mm and that it was manufactured in Germany. The second line identifies the importer as Century International Arms Inc., and tells us that they are located in Saint Albans VT.
The importer, Century International Arms Inc. is still in business today and offers collectors a wide variety of firearms from around the world to choose from. The import law that is mentioned above can be referenced by viewing the gun control Act of 1968, Public Law 90-618 and under Subpart F-Conduct of Business sub-section 178.92 (a)(1) Firearms.
Lugers at Radom by Charles Kenyon
German Handguns by Ian Hogg
German small arms markings by Joachim Gortz & Don Bryans
History Writ in Steel by Donald Maus
The standard directory of proof marks by Gerhard Wirnsberger
Official guide to gunmarks by Robert Balderson
Mauser military rifle markings by Terence Lapin
Handbook of military rifle marks 1866-1950 by Richard Hoffman & Noel Schott