Any help with Sig history on RCS?

I just bought my first 1911, .45 Auto, of course. It was manufactured in May 2008. Per a Sig sticker on the blue plastic case, it is a 1911 RCS 4 inch Nittron. The manual which came with it has specs for for three models : Full Size, Carry, and Compact. Using the measurements, mine is the Compact. However, the weight listed is 2 oz. higher than what I get from my scale, Sig says 30.3 oz empty /w.o mag. I get 26.8. The website shows this gun but the slide is engraved RCS mine isn't. My manual says 6 round mags (2) but the sticker says 7 rounds. So what's going on here?

CORRECTION: the slide is marked RCS