Interesting snippet in El Clarín:
"El buque noruego Sophie Siem zarpa con un minisubmarino de la Marina de EE.UU. a bordo para sumarse a la búsqueda del ARA San Juan. Unos 60 hombres trabajan para adecuar la estructura de la popa del barco."
So some 60 workmen are having to modify the deck of the Sophia Siem in order to load up one of the US rescue submarines - in other words the US assets are not fully ready for deployment.
Seems like SPAG are ready to deploy. One SPAG unit is on the Clyde, steaming from the Falklands. I would guess that the standby unit flew in on the A330 and are readying to deploy from the C-130 at CR.