I have no clue to the rhyme and reason of Kimber's mix and match of carbon and stainless parts. My TLE II has a blackened stainless frame, thumb safety, slide stop, and barrel bushing. The slide, barrel, and grip safety are carbon steel. FWIW, I just cold blued the barrel with Oxphy-Blue. It's held up well and is an easy touch up if needed.
All that said, I would have gladly taken a carbon steel barrel in my new Colt Government Model if they would have paid better attention to the fit and finish of the rest of it (in particular, the faulty extractor). Well, at least it didn't have an offset recoil spring tunnel like the other three I looked at did.
Regards,
Greg