The colour ruling could change depending on the combination. Very similar colour option for Buckskin and White would see the front and rear seats in white, door trims in white. The A pillars, sail panels, rear armrests, sunvisors and roof lining were white. Parcel tray probably buckskin. Carpet, dash, console in buckskin.
Being a TA in 1977, door handle escutcheons, steering wheel and steering column were black.
If original trim and upholstery there is likely still bare vinyl and plastic on the rear or out of sight showing original white or buckskin to confirm.
A later 'version' but you get the idea. 79 Camel Tan/Oyster interior.
https://firebirdtransamparts.com/tec...ameloyster.jpg