I have a 91-92 wraparound spoiler I bought for my 87 GTA as the old rubber one was junk and I have a few questions about it. The first is was there any gaskets between the spoiler and hatch lid or maybe seals that went around the bolt holes? and second did the wire from the 3rd brake light come out from behind the plastic panel that runs across the headliner in the back? Thanks

IIRC, there's no gaskets or seals involved to sandwich between the spoiler and the hatch. I think the third brake light was located inside the rear spoiler on the 87 GTA, so there would be no 3rd brake light harness lead inside the headliner on your car.

Easiest thing to do at this point is to get a 91-92 Formula or T/A hatch with the glass and all, as the mounting locations for the spoiler are also different than the 1987-90 spoiler, so you will have to drill new holes for the spoiler you just bought if you want it on your existing hatch. Then comes the difficulty of the third brake light, which was located on the spoiler from 1987-90, then moved inside the rear hatch glass on 1991-92 models. Basically you're going to have to do some fabrication to get your current setup to work with the new spoiler. Not worth it in the end IMO when junkyards are selling entire hatch/glass assemblies for under $100.

I have the glass and the spoiler so there is no drilling or anything like that. If there is no seals or gaskets then what stops the water from getting in? I have the hatch for the 91-92 spoiller so its ust a bolt in.

the spoiler i have sitting int he garage, had some bits of old gasket material on it, probably a simple foam runner strip between the spoiler and deck. You can pick up universal foam rubber weatherstripping at most hardware type stores, maybe 1/2" wide and just rin it around the pedestal. that should work, or you can run some RTV around the edge of the pedestal before you bolt it on, then wipe off the excess.