I think supply and demand function to inflate their European prices. I don't think many were exported. It's more a reflection of their relative scarcity there than their quality as firearms.
They're all from the same Houston shop. Different runs were made for different distributors, who evidently contributed to the specs for the guns each one bought. I say this because there is variation in the fit and finish among those brands. Unless I'm mistaken, SPM is likely the name of the shop that made them, and all the rest are brands (I perceive Aimco to be the "house brand."). Serial numbers seem to appear in different sequences, and are probably specific to whoever ordered/branded them.
Typically, the fit is quite sloppy. Finish can vary from fairly straight to over-buffed with wavy surfaces where they're supposed to be flat. Problems with peening and upsetting occur, quite often on the ramps on the frames, where the toggle knobs hit them, and on the undersides of the knobs themselves. Chalk this up to the relative infancy of applying stainless steel to firearms, which may have improved during overall history of their production.
Some parts interchange with originals, some don't. Magazines are in the latter category, originals are very loose when installed in a stainless gun, and some don't lock in at all. A mag for a stainless gun won't fit into an original's mag well.
There are pics representative of the various configurations they produced in both calibers, in the forum's gallery section. Extractor design varies throughout, for another example.
Since Stoeger owns the copyright for the name "Luger," only those will be marked as such.
I've owned a couple. One was pretty much a P.08 in configuration. I bought it from a forum member and sold it recently to another. We fixed the top end to be flush with the frame, which is a problem mentioned in this comment on a thread in Jan Still's forum.
https://luger.gunboards.com/showthre...5030#post55030 I addressed the upsetting at the toggle ramps as well as some kicked up by the face of the breech block at the top, rear of the receiver with a file and some emery paper --lucky it's stainless with no finish, so the rehab is invisible.
I still have the other, a "1900/2000" which was Cerakoted black over the stainless at the factory. It has dished toggle knobs (no toggle lock), pencil-taper barrel, and is chambered in .30 Luger. serial number "AE 040 of 350)." I figure this 100-year commemorative series was probably the last of them ever made.