It’s a joint weapon-both partners would have to agree for sales to go ahead.
BTW,Clintoon did purchase of a few Russian supersonic missiles(the KH-31 Krypton) for tests with US Navy systems instead of developing domestic systems .The Ruskies were canny enough to sell downgraded variants!!
We have our own sea-skimming supersonic drone now, the GQM-163 Coyote.