What poodles said is 100% true..
I have installed 89+ 3 piece wings on my 86.5 and 89, the 3rd brake light is only held on by two screws, and the connector plugs right into the LED bar on the wing. Also, I have switched out my yellow taillight failure boxes infavor of 89+ LED boxes (keeping in mind N/A sport package wings were LED as well, albeit 1 piece), and I also swapped out my trunk shocks for "red sticker" turbo shocks...
just make sure you clean up, years of grime getting stuck under there will leave an outline..