Mine is an 88 firebird formula with one of these wings

http://carphotos.cardomain.com/ride_...0018_large.jpg

http://carphotos.cardomain.com/ride_...0021_large.jpg

do these cars have third brake lights, mine didnt

is it illegal, most people think it is so old that it does not require one

and where would the wiring harness be if it existed for me to possibly install a third brake light

 

I have an 87 and my wing is different, mine has the middle brake light located just under the middle of the wing. If yours came with that kind of wing then no it wouldn't have a third brake.