Cockrocket (...and what kind of name is that anyway?) I think you might be a bit confused. It doesn't matter if they had long or short tails, the racing versions of the McLaren F1 are all called "GTR"s. The car that Thorst is inquiring about is the F1 GT - a road legal version of the long tail GTR.
The factory only made three of them and still has the prototype '56XPGT' seen in this photo.
>8^)
ER