I assume your are talking about the Dantinne car. I think it is a genuine Group 4! In the Wyss book on 308/Mondials there is a picture of what I believe is this car. This pic was taken by an American in the factory! No confirmation was given in the book, but I am pretty sure it is not a replica or modified car by the owner. It is a regular visitor to the SFD!
Niels
Niels