84 or 85. 86 had the third brake light on the top of the window. I think that rear spoiler was used through 85, whale tale may have been an option (my 85 had the whale tale, also convex wheels which I think were the equivelant to the w72?) I think that aero package may have been an option in 84. I will say 85, nice looking car. Mine was silver with a grey bottom accent.
As to the original intent of this post, good luck on my part, LOL, about the only firebirds I see in my area are in my garage. I will keep an eye out though.