These were on the lower rear portion of early 1967 390 GT Cougar fenders. In later 67 and 68 the separate G and T letters were used on the Mercury Cougar. Comes with replacement tubular nuts as shown. Other applications include 1967 Mercury Cyclone GT and 1968 Mustang GT.
The GT rectangle badge was used until sometime between 11/22/66 and 1/28/67, after that, the individual letters were used.