328GTS Black skirts and sills

Hi. I have a 328GTS in red which has black stone chip finish to the sills, front spoiler and rear skirt. Does anybody now if this was how the cars left the factory or if was likely to be applied at a later date. Most cars including colours other than red seem to be similarly coloured but I have found a few where these panels are body colour. Any thoughts please?
DickB

 

Thank you. Its nice to know its how it should be.