They look to be Mille Miglia Spyder 2s. They were available for a time in the US and are long out of production. They are nearly impossible to find in decent condition especially with the 5 X 100 bolt pattern.
Is your Fastback GT's trunk seal shot? My Gen IV replacement GT trunk seals with miter double bonded corners are now in production. $95 shipped to the US (contact me for international shipping rates) More info can be found here GT Trunk Seal Project