On the bottom side you will see a little plate with 2 rivets. Remove that plate then you will see the clip that holds it in. Pull the clip out and it should slide right out.
I just shaved the trunklid on my 92 vert and had the same issue. Turns out there was a second clip inside the trunklid as well as the outer one. Look up into the openings undernneath the outside lip. Once you get the inside one pulled it will slide right out. Hope this helps.