I also got another CE1000 Expanse and it is also slightly different, the barrel is stamped "5.56 NATO 1/7 C P" rollmarked not engraved like my last one, the lower looks like recent M4 carbines i have seen, S/N range at LE406XXX range. The lower has a keyhole forging and the upper has a C stamp and square forge mark with T marked rail and usual M4 above the gas tube. The bolt carrier/bolt is the same, unmarked M16 type. It also had actual M4 handguards installed, but sadly no upgraded hammer or mag release like yours. Is Colt back to using misc parts on their rifles again?