HAHA
Ok, my old RS1600i as above ( genuine car, covered in a magazine back in 1995 - Fast Ford I think ) had XR3i spats on it, which was a bit of a joke at the time when the RSBB was the place to be on the net due to the RSi only coming with 9 official options, the 10th being the fabbled Spats.
I maintain ( as I removed one by accident ) they were fitted at factory and the paint work and quality of the metal behind tended to agree. Obviously the RSi faithfull tell me I am talking bollocks BUT there was evidence to suggest it as I have seen other 16i's with spats on and had a hand in breaking an ex concourse Caspian Blue one with them.
It stands to reason that if you're a paying customer in 1982/1983 and you wanted XR3i Spats on your RSi then Ford would fit them... hence... the Fabbled (un official) 10th option joke.
Hope that helps.