1940 byf question

[PaFrank]

New guy here..........

I bought it 35 years ago, and if I remember, I was told something about the 1940 byf being special, but can't remember why.

Here is the dope on it.

Frame: 323 proof mark below looks like a stylized F with a crown
Receiver eagle proof on right side, 1940 over chamber. 323 on left side
sideplate: 23 No number stamped on underside.
Sideplate latch: 23
Toggle pin: 23
Extractor: 23 with a proof mark
bolt:23
front toggle link: byf and 23
Rear toggle link: 23
Barrel: on underside, 323 over 42 over 882 or 832
Saftey: 23
Saftey bar: 23
Trigger: 23
Firing pin: unmarked that I can see.

2 aluminum bottom mags (fxo i think) and an original holster is only fair shape.

Would this be considered all matching? I'm concerned about the barrel, but the witness marks line up perfectly.

I'm not sure where to look for a letter suffix, but didn't see any other marks on it.

So my question is, What do I have? Anything special? or just a run of the mill mostly matching luger?

Thanks for your help!