91 Sportline wheel colours

Hi all,
I've seen lots of pictures of Black and Red sportlines with alloy grey coloured wheels rather than the black they are supposed to be; mine are alloy grey also.
The wheel type is the same just wondering if anyone knows whether this was an option at sale or simply a re-dip? I'm trying to decide whether to keep them as is or return to original and want to know what original is…
Thanks for any help
Book

They would have come with black centres originally.  Plenty of other models came with alloy coloured ra's so probably just a case of replacing damaged etc wheels over time.

Thanks ew.
Gives me a little food for thought.
Book.