That appears to be the case, and Johnson is still fighting to get in the top 3 at GK.
It remains possible that one of our other players could end up in the mix. I seem to recall that Santi was on Uruguay's provisional roster for the most recent qualifiers, and he played at every youth level for them. Taty has to have at least an outside chance for Argentina - especially if he signs for a good club in Europe this summer.
There are also several alums who could get a call up - Reyna, Scally, Matarrita.