Some of these ships are designated USNS and some are USS. I could be mistaken, but I thought all were commissioned as USNS. And as far as I know there were no modifications prior to be redesignated USS. All this said, what prompted the change to USS?
The Navy is moving away from the USNS for the ESBs.
The ESBs are all scheduled to be USS for now on.
Basically the ESBs are now being designated as warships and thus USS. This probably indicates they’ll have Navy Crews, at least partially and will carry some level of weapons. I wouldn’t be surprised if they’re thinking about Drones.