Parts fit but poor documentation - IMG AR-10 .308 12 Gauge 19in Complete Upper Receiver w/Two 5 Round Magazine

The upper fit to the dpms lower and the mags fit snugly in the well. Package lacks documentation - the three chokes are unmarked as to what choke, (impr cyl, mod, full) they are, no recommended shell type (low brass v. tall brass), nor size (2 3/4 or 3") provided either. Would expect more information and no web sites given to get more.