Sigs with nitron slides wear out finish on the frame faster than two-tone sigs or older W. German stamped steel guns. It's normal, and there's not much you can do about it other than using a good lubricant (grease, not oil or CLP).I saw some of the rail wear on your p229. I'm guessing this is normal with sigs?
I noticed some rail wear on the nitron finish after only 500 or so rounds on my P226