The launcher cut is now dropped from the spec for the present, and future contracts. Like quad rails, the forward assist, and the disposable magazine, it was an institutional requirement, not a superior enhancement of the design. The cuts are now proven to be a weak area and cause early failure in back to back mag dumps.
Moot point in a semi auto gun; for military use, no longer wanted on a carbine. The NEW grenade launcher can be used with it's own stock and chest holster. The cuts are now curio and relic collectable fodder, like carry handle uppers. Nice period dress up for an aging retro Barbie.