It's a little complicated since the Tactics Advance art was less consistent in that regard. In some of it they had claws on their hands and clawed digitigrade feet, in others they have no claws and are wearing flat shoes.
XII did have these features though and I would have liked to see them for sure, but they were almost definitely not modeled onto the XIV versions because of the difficulty it would involve. All flat-footed shoe models would have had to be remodeled for Viera to accommodate this. They were at the very least aware of their unique feet though, since the 2015 concept art has them.
This is a very similar situation to the Hrothgar as well where their First counterpart race, Ronso, had Digitigrade feet in their game of origin. They also only have claws while wearing their racial starting gear and lose them if its removed, as it would again require remodeling gloves to accommodate them (wouldn't have minded them pulling an Aion and making them only disappear when gloves are equipped tho). We'll have to see if we meet any Ronso in ShB but I wouldn't be surprised if they just had Hrothgar models with no modifications, despite their FFX appearance.