They’re saying that want the capability in service at the earliest achievable time; that probably implies at least one boat off a hot (overseas) production line. There have been indications for some time that the US would like to go back to two yards building Virginia’s, so that might be a possibility. Given the slow start to the successor SSBN in the UK, and the nearing end of Astute production that’s obviously another although a Brit design would potentially introduce a new combat system philosophy which might not be desirable.
This announcement is so paradigm changing that I wonder if a CV is next….(hat, coat,,,,)