I would wager that they are heat treated as is customary in this level of finish...but I don't know for sure!
As far as color, it can be controlled if you have precise control of the heat levels. If you've every blued a piece of metal, you can watch it go through multiple colors and in that, varying degrees of blue.
As far as imperfections go, if the piece is perfectly polished and cleaned, you can get an amazing Blue finish with really no visible flaws. But, it is NOT easy! Believe me as I've spent the better part of a day re bluing a set of screws for an antique pocket watch.
Speaking of Blued screws, that is the one thing about this movement that I really don't care for. Traditionally, blued screws were usually done on lower grade finishes and typically paired with guilded movements. Polished screws were usually used with nickel finished or "white" movements...
Don