Technically, tga textures are the same format in both games so dropping "N_RepSold.tga" into the override should do the trick, that "N_RepSold.txi" file on the other hand... probably won't work.
@Dark Hopewould have to fix the txi to work in TSL should the texture not work. Other than that, she would need to make a texture for the male Republic Soldier helmet NPC, female Republic Soldier NPC, the TSF male and female NPCs and maybe even the male and female Republic and TSF Officer NPCs.
Also, I think this mod (if you rename the male Republic Soldier texture right) can work with JC's Female Republic Soldier fix mod:
Not even change the names, just outright drop the tga into TSL and you're good.