Diemaco-marked A2 upper receiver with A2 sight assembly, FA, and dust cover. From a recent production LE6520. Had about 400 rounds through it, and shows wear commensurate with that use, but is 98% overall. Small amount of finish missing at rear of ejection port where casings hit, and internal marks from bolt assembly.
This receiver also has "M4" feed cuts, although these appear to be "in the white." This is probably due to the cuts being added by Colt to the fully finished receiver from Diemaco. Diemaco is a Colt subcontractor, and is now owned by Colt. These cuts are FROM THE FACTORY, not added by anyone.