All of my new Sig's accept for the M11A1 have barrel finishes that look like a bake on paint. Don't look anything like Nitron to me. Nitron doesn't adhere well to carbon steel. It almost comes out looking like parkerizing. My M11A1 barrel has a roughy shitty looking finish.

My 357Sig P229 "Carry" barrel suprisingly came with this finish applied to it..