Hiya jrkrk and thx for the thread, sorry I don't have the definitive answer, but have had factory out of the box the normal steel colored, and some kinda grayish with a micro-spray on them,and the black finish on others. Believe the only factory gun with an extra barrel was the checkmate and the spare was black and the other polished steel. My guess the black is something that prolly prevents rust, it will rub off with cleanings over time,or with a buffing if ya hate it. Have had Stu at czc just buff out the dull gray on a barrel when it was getting other work and it really came out nice, i.e. when you can see the serial across the room. Generally prefer a less shiny cz and have been known to send out triggers and frames just to poly black, barrels not so much. Cheers. Be well.
