Gurney only drove the car once or twice in 1968 from SCCA records........and unfortunately with no notable results. 1968 was NOT a good year for Ford.
That said, there were other Mustangs that ran in the series in 1968, so there MIGHT be justification to further develop the tooling to make a proper Mustang T/A. As much as it pains me to admit, Chevrolet ( Penske/Donahue ) ran away with the 68 T/A Championship by a wide margin.