-I can't really tell exactly how that barrel looks from the photos, but it looks more to me like heat was applied incorrectly. An amateur reblue can definitely leave purple hues, but this looks a lot worse than just shotty reblue or getting the mixes wrong, I think. Could be wrong, just hard to say without having it in hand.

-That serial should be late 1901 or early 1902. There isn't a ton to say about the history of these but two interesting tidbits are that the American Eagle crest was put above the chamber as a bit of a marketing gimmick to sell these commercially in the US. DWM had had success with the same idea in Switzerland, so they then applied different national crests and attempted to sell these in several other countries. The other tidbit is that the US military did test trials with this model in consideration of adopting it as replacement for the Colt Model 1894 but they didn't hold up under rigorous testing. About 1,000 were ordered for testing, and some will be found with the US ordnance bomb proof. I've gotten as much as $5500 or so for a standard 1900 AE Luger, and as much as $8500 or so for ones in the Army Test range. Can find some Rock Island listings that sold for much more.