[DonVoigt]

The barrel was originally made by Simson- likely in 1923 from the "3" seen on the barrel.
It was added to the 1940 luger by a third party and proofed as a "repaired" pistol as indicated by the
added 9mm, E/N, and E/J .

The E/N is a proof mark, and the E/J indicates repaired (in this case likely the barrel replacement and perhaps other small parts).

Repair is also noted by the non-standard numbering on the replacement(42 code) side plate, and rear toggle. The HZa marked extractor is also a replacement.