mmmm i also have a 96 and for some reason my rear right seat-belt has water stains on it... I cleaned it off thinking it was dirt or something, but this damn stain came back.... im gonna check my wheel well as well.

I'll bet you find a hole.

if i do can i use aluminum tape or something to temporarily patch it?

That will hold for a little while. You can pop rivit sheet metal over the hole after you clean up the rust. Then coat it with some truck bed liner

Another place to check is the antenna opening. If that is not sealed properly, water can get in there; also through the antenna itself (normal) but there is a rubber drain hose connected to the bottom of the anntenna. If that hose has come off, or is blocked, or the other end it not inserted into the exit hole, it could allow water into your trunk.