Topic on Talk:UPK Explorer
No, the textures are extracted as the names they appear in the UPK, then injected in the same way. We don't use hex codes.
You don't need to do the Texmod method with the exe. Just extract UPKExplorer and TFCInstaller to a location and then setup a working folder (Ex, D:\UPK Working), then you open the game, search for the textures, export as DDS, edit them, move them to their equivalent Imports folder and create a texture pack.
It was tested on the Steam version.