Well, in my folder Data\models_unit\textures there are several files named as:

OFFICER_BARB_GENERAL_XXX.TGA.DDS (XXX is the faction name)
OFFICER_BARB_LESSER_GENERAL_XXX.TGA.DDS
OFFICER_CARTHAGE_GENERAL_CARTHAGE.TGA.DDS
OFFICER_CARTHAGE_LESSER_GENERAL_CARTHAGE.TGA.DDS
OFFICER_GREEK_GENERAL_XXX.TGA.DDS
OFFICER_GREEK_LESSER_GENERAL_XXX.TGA.DDS

Is that what are you looking for?
Cheers.