Same files, although I wonder if that is gonna work even, I believe Blizzard will detect that you modified their casc files and then auto-download the new ones.
But UI files you will be looking for (assuming race is human, but same concept to orc, undead etc) is
Console/Human/HumanUITile01
Console/Human/HumanUITile02
Console/Human/HumanUITile03
Console/Human/HumanUITile04
Console/Human/HumanUITile-InventoryCover
And assuming you wanna change the top bar (clock etc), then the file for that one is called "HumanUI-TimeIndicator"