Subject gun is an Erfurt, chamber date 1912. Serial number is 454, which puts it very near the beginning of production that year; estimated 1912 production is 21,000 units (Still, "Imperial Lugers", p.15).
This Luger is unit marked 67.RMG.35. meaning that it served with the 67th Infantry Regiment, Machine-gun company, as weapon #35.
This pistol is a perverse combination of excellence and frustration. It is somewhat better than 85% of its original finish, and 40% straw. All the serial numbers match, including the grips, and all the small parts are inspector stamped, as per regulation--except--yes, you observe correctly, someone put an Artillery barrel on it!, a commercial barrel to boot ("Germany" stamped beneath the sight on the right side, no numbers or proofs) reducing the pistol to marginality as a collector's piece; the sideplate is commercial, as well. Although the trigger number is the wrong size and a very different font, and looks like it has been ground and re-stamped, under magnification faint remnants of the original 54 are visible.
A holdopen has been added. There is one Revision Commission stamp, on the front of the trigger guard.
I am told that the magazine which came with this Luger is an armorer's replacement--it has two inspector's marks, and no serial number. The inspector's mark is just visible on the grip screw in this picture, as well.
--Dwight