It was never even a question about it until seeing that page and as easy as looking at the paint code stamped on your car.
Solar Gold 50 was the only Gold used on these particular Firebirds 76-81 era for body, which included Y88 and regular TA and Firebird in same gold paint.
Special Edition Gold 55 was an accent colour only, used on grilles, wheels and light surrounds of SE TA's and the same areas plus body stripes on 2-tone W50 Formulas with gold option. Also found on golds rims where it suited the combination of paint, decals. interior of regular Firebird and TA models.
Or simply put, there was no code 55 Gold option for body paint.