I think my trunk leak is coming from my tail lights. looks like they use some adhesive foam strip around the back of the light.

should I get this: https://www.walmart.com/ip/Duck-Bran...s-2pk/17133825

or keep the existing gasket and use permatex gasket maker? I'm worried the weatherstrip wont keep water out.

 

have you taken the light(s) out and inspected the area? If water has been getting in I'd expect to see signs on the back of the light or the edges of the opening or both ..... this IS a rust problem area on GEN1 cars .... I've seen some REAL MESSes around the tail light opening and when you begin to probe it gets MUCH WORSE ......

I'd be careful about slapping some new foam to build up the seal .... too thick or wide and the light isn't going to sit correctly in the mount.

I'd start simple and check if the light is TIGHT ... pull it and look for signs of water intrusion and anything in the seal area that shouldn't be there .....

to remove the tail light, pop off the trim ring. Just use something to pry at an edge and it will pop off ... something plastic is better than metal to prevent scratches .... with the trim ring off it is easy to see the mounting screws. Remove these and the light pulls out (may require some wiggling)

 

yes I removed the lights, it was wet behind them.