Let me check my horse's mouth

As we already know, out of the 5500-odd that were built, 500 were shuffled away to a storage plant....I'll finish the story when I get back.

More info from the Horse's mouth, aka Mike Moreton who was put in charge of the Sierra Cosworth 'evolution', ie, the RS500. You'll find this in a fantastic book called Rallye Sport Fords - The Inside Story, incidentally, by Mike Moreton. There's a stonking big chapter about the RS200 too.

500 black ones were requested, but a handful of White and Moonstone interlopers slipped through the net. They were stored at Frog Island in Essex, one of Ford's holding areas where they waited, still in '3-Door' form. They then got shipped off to Tickford at Bedworth for conversion. The parts that were swapped, like the front bumper, intercooler, etc, were sent back to Ford to go in the spares bin.