It's an interesting question and open to some debate.
I personally lean towards it being fluorescent although some photos of the early season car make it look more like a bright red.
You have to take into account that colors can appear different in photos depending on equipment and lighting - I've found photos from the same rally where it looks bright red in one and is definitely fluorescent in another.
See example:
http://www.tenamp.com/real/mcrae-cat...rava-99-01.jpg
https://www.ewrc-results.com/image/13382/