As I undserstand it there were 401 cars built. The Bill Mitchell Mangusta / Corvette is car number 8MA670. It was not built at the end of the run. I have had that car since September of 1969.
I have heard that the last car built, the on that is #401 ( I do not know the actual number), was built for Gene Bordinat from parts after he became Design VP for Ford. I went to his funeral when he passed away and discussed the car with his widow.
Ford Design or Gene Bordinat did not understand the Giugiaro design and made alterations to the car that are completely out of character with the original design.
Forgotten is the fact that the Mangusta is built on a racing chassis and was intended to be a racecar for the street. This is covered in the owners manual by de Tomaso himself.
7 inch rims in the front and 8 inch rims in the rear.
BELLA MANGUSTA, The Italian Art and Design of the De Tomaso Mangusta
covers all of that.