[Heinz]

You need to get to section III of the C and R list, for C & R that are exempt from the National Firearms Act. The following are from that list. ( I am also a retired lawyer, so I read the fine print)

Luger, 1920 Commercial Artillery Model, pistols mfd. by DWM or Erfurt, having undated
chambers, commercial proofmarks, and bearing the inscription “Germany” or “Made in Germany” on the receiver and accompanied by original, German mfd., artillery-type, detachable wooden shoulder stocks.
Luger, Artillery Model, pistols having chamber dates of 1914 through 1918 or 1920, having German Weimar Navy markings consisting of the letter M over an anchor and a German Navy property number accompanied by original Artillery Luger flat board stocks, bearing German Weimar Navy markings of the letter M over an anchor with or without Navy property numbers.
Luger, DWM, original models 1904, 1906, 1908, 1914, and 1920, Naval pistols, cal.’s 9mm Parabellum or 7.65mm, in both the Commercial and Naval military varieties; in both altered and unaltered barrel lengths in the Model 1904 and in both altered and unaltered safety markings in the Model 1906; with original board-type detachable shoulder stocks bearing brass or iron discs, with or without markings, or, if without brass or iron discs, being of the Navy flat board-type. This exemption applies only to the listed Naval Luger pistols if mated to the Naval Luger stock and will not apply if the Naval Luger pistol is mated to the Artillery stock. The Naval stock has an overall dimension of 12-3/4", a rear width of 4-5/8", a front width of 1-1/2", a rear thickness of 9/16", and a front thickness of l-3/16".
Luger, DWM Pistol, Model 1900, 1902, or 1906, cal.’s 7.65 Luger or 9mm Parabellum, having the American Eagle chamber crest, and barrel lengths of either 4" or 4-3/4", with original detachable Ideal shoulder stocks and Ideal frame grips.
Luger, DWM pistol-carbine, Model 1920, cal.’s 7.65mm or 9mm, with accompanying original commercial type shoulder stock, with or without forearm piece, having barrel lengths of 11- 3/4" to less than 16".
Luger, DWM Stoeger, Model 1920 and 1923, semiautomatic pistols, cal.’s 7.65mm or 9mm Parabellum, in barrel lengths of 8, 10, 12, and 12-1/2", having either American Eagle chamber crests and/or Stoeger frame and/or upper receiver marks, having either standard, Navy or artillery rear sights, having extractors marked either "Loaded" or "Geladen" and having frame safety markings of either "Gesichert" or "Safe”, together w/original commercial flat board stocks of the artillery type, which bear no S/Ns or military proof marks, but may incorporate a "Germany" marking.
Luger, German Model 1914 Artillery model pistols, mfd. by DWM or Erfurt, having chambers dated 1914-1918, bearing Imperial German military proofmarks & accompanied by original, German mfd., artillery-type, detachable wooden shoulder stocks.
Luger, Model 1902, Pistol-Carbine, cal. 7.65mm Luger, with original commercial type shoulder stock and forearm and 11-3/4" barrel.
Luger, Persian (Iranian) Artillery model, pistols, as mfd. by Mauser prior to 1945, accompanied by the original artillery type, detachable wooden shoulder stock, bearing a S/N in Farsi characters stamped into the wood on the left side.
Luger, semiautomatic pistol, certain variations with Benke-Thiemann folding shoulder stock.