Afternoon
I was wondering if the other part to the US Navy question was the USAF. They did have the JPATS competition in the nineties.
Hit the nail on the head Sinco, yes this was to be a JPATS contender but the project was cancelled seemingly (from what I have read) before the tender process started because of a change of emphasis on the requirement.
The aircraft itself was a product of an international partnership, as well as support from a US manufacturer.
Not Korean RD