'NSN' is a valid FFL log book entry IF the gun was mfg'd that way.
..and some .22rf long guns and some shotguns were before GCA'68.

Prior to GCA'68, all handguns (and centerfire rifles) had to be serial numbered if mfg'rd in the USA.

The only thing that changed with the implementation of the GCA68 was that from then on (12/'68 and forward),,cal.22rf long guns and all shotguns were ALSO required to be ser#'d by their mfg'r.

The removal, alteration,obliteration of a mfg'rs applied ser# or possession or sale of a firearm with such a ser# has been a Fed. Felony since the Federal Firearms Act 1938 (FDR).

Wikidedia can't seem to get this right.


As to the Luger, It looks like a Refinished Luger that also has some replacement parts on it. Some of those replacements may/may not have been refinished. Or they may have been refinished at another time. Not the same bluing batch.

The toggle is 'blank'. That isn't all that unusual in a heavy refinish. If pitted there the flat area is easily taken down to elliminate the pitting and the marking disappears.
The toggle looks taken down considerably in the pic, almost to the edge of the chamfer on both sides of the toggle block.
Proofs disappear from the sides of the upper and the sides of the toggle(s) during polishing also. They are not that heavily punched anyway.

It looks like there is a Ser# on the bottom edge of the side plate.
If so that would be a Commercial Model side plate and that style Ser#'g placement.
But the side plate could be just another replacement part w/another #.

A replacement bbl perhaps. Those un#'d/ void of markings but finished bbls were very common at one time not all that long ago.

The Frame Ser# can be ground off on a belt grinder in a couple swipes during a refinish if you'r not careful or watchful,,or don't care.

If it was indeed a Commercial model, there would not have been a chamber marking to begin with.
There would have been a toggle marking (DWM..)
A simple commercial proof on the front left side of the upper most likely (Crown/N) and then the much less crowded commercial ser# marking placement.

The lack of frame ser# is something for others to sort out. It's been beaten to death here many times.
All I can say is everyone knows what the simple Fed Reg says and it hasn't ever changed since 1938.
..and Parabellums weren't mfg'd w/o ser#'s.

JM.02