It was a real Cup, but it's hardly standard anymore, having had various bodywork alterations and a different engine. Maybe it could be made into a good track-day Ghibli special, but reverting it to proper Cup spec would be very expensive and possibly even impossible (through lack of original parts). This is the highest mileage UK CUP and the most played about with and non-original. Hence the low price. And given the mileage and the history, whatever you did to it, it would still be the least desirable.
I see it failed its recent MOT, so will need to be collected from the auction on a trailer. I can see why its being sold by action. (Well, I say "sold" - no one wanted it last time out...)
Buyer beware, I'd say.