IIRC if an item has a complete static texture then it wont recolour, untextured items use the game's colour ids.
I'll be nice & do a little experiment. BRB with results...
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3D objects don't recolour even if they aren't textured, seems the colour ids are now fixed; and only one for each body part can be active which I expected would be the case (multiples will have been a glitch)