What a great site this is!
I have been doing research all night on a Luger I picked up at SAR West today- it was sold as a 'Tibetian' Luger, but the price was right. Turns out it's Thai Police
No Naga mark on mine, but it has the Kor Tor front strap markings, and what looks like 45214 in Thai numbers.
Mine's an Erfurt 1917 non-artillery (standard barrel). All matching (period correct wood bottom but not number matching mag) and mechanically sound, but with pitting under the grips (typical of anything used near the ocean- I've seen Shanghai Piloce guns look similar, or usually, worse!).
Nice to see you guys worked out a hypothetical timeline already!
-Dave