I would say that if you can restore your GT tailights with repro lenses for $400/ pr original pairs in excellent -LN shape should bring a bit more. Before Goodyear's repros came about, these lights were going for up to $1000 per pair but now that you can fix your own the price has dropped.
As for the price of these lights, you can buy a new custom taillight panel, with lenses for less. I tired of the old fashioned 80's look so I chose that solution on both my fastback and notchback.
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "