Spartan, I had the same question about a new SP 2340 I picked up Friday. Out of the box & before I ever fired it, the barrel had a (rather large) shiny half moon on top & one on the bottom of the barrel where the slid (bushing if it had one) contacts the barrel.
The dealer, who I know very well, told me that this is normal & infact proves that Sig fired the gun after assembly. He said that the wear is because of the tight fit, but even then is only cosmetic, i.e. only bluing deep.
I have only put 50 rounds through it, as that it rained all weekend, but I have noticed that even with so few rounds that there are some lighter "rings" or Half moon wear marks appearing on the barrel between the chamber end & the orginal larger marks.
ALL: I would sure like to hear some other opinions as to if this is all normal or not.
I'm a rifle person & when it comes to Auto-Pistols you will not find a much bigger novice around!
Other than the marking on the barrel, the gun functions great & is very accurate (he said after only 50 rounds...)
K