It is, and if adopted, it likely will be built at the new Georgia H&K facility. I haven't been around that area since Christmas, so I don't know how progress on the facility is coming, but the XM-8 is a long way from adoption and production anyway.
But production here does not preclude production elsewhere as well, or sales to other users. And it may be that as with the 7mm Mauser bolt-action repeaters we faced in the 1898 war with Spain in Cuba, or the stamped MP44/Stg44 Sturmgewehren of the German assault troops of WWII, someone else will jump on the idea of an advanced small arms platform first, and we'll pick it up only after deficiencies in our current hardware become too obvious, probably as a political football.