Hmm, that's mainly to do with import/export though right? If its sitting in international waters (which it may or may not be) then that isn't you exporting it from the US. In fact, they sent the weapon outside the US themselves.

Also, maybe you wouldn't sell it outside of the US, but inside.

Wouldn't stopping me from just even simply owning this infringe my right to bear (massive) arms? :)