Moving to the upper receiver, its evident that these are engraved with T numbers. The machining is even, and free of chatter or tool marks. The finish is even, and a deep satin black which is a dead match for the lower receiver. The ejection port cover snaps into place without needing undue force, which is more than I can say for some upper end weapons I've dealt with lately. The spring is correctly in place on the ejection port, and is silver in color.