Flatsgfuide,
Yes, the frizzen is annealed prior to polishing and engraving and then is re-hardened. (These are cast 1090 and are a pain to re-harden, at least for me. I follow the Chambers instructions for hardening their frizzens, but the oil quench just does not cool the part fast enough so I use brine. Works better, but may take two or three tries to get hard enough to spark.....topic for another post).
As for the finish on this lock, I will case harden it and then polish off the colors. Not sure yet if I will just leave it bright, as I have with some of the others, or "bronze" it like I did on the barrel of this rifle.