I like it very much. So from the responses above I assume it's just normal bluing, however that the surface metal was more finely polished than I'm used to seeing, and that the result is a shinier finish.
I'm not sure how many Colt 1911s you've seen before, but prior to the 1990s they were usually finished with sandblasted rounds and a mirror-bright polish on the flats. Since then the 1991 models were at first completely matte finished, but around 2000 or so Colt began to apply a brushed, semi-polished finish to the flats. Not as bright and smooth as on the previous guns, but still a lot better looking than the all-matte finish. When the Series 70 repros were introduced they got a much finier finish, about a 400 grit polish on the flats, but even they weren't mirror-bright like the original 1970's-era guns were. I thought the 1991 and XSE models were hand polished on the flats to a lesser degree, like maybe 240 grit or something, but from watching the various Colt factory tour videos on YouTube it looks to me like the flats are surfaced on a machine after the parts have been sandblasted, and then left that way to be rollmarked and finished without any additional polishing.
BTW if you want to brighten up the flats a little more you can apply some Flitz polish to them and rub off using a cloth. Just don't overdo it or get any on the matte areas. A member suggested I do the same with my new blued Series 70 and it really made a big difference.