Fender attachment?

[julie at menloparkrandd.com (julie@menloparkrandd.com)]

I will be replacing the fenders soon. During the derusting, I found something like silver tape over the bolt attachment points. All of that tape, on both sides of the car has been removed and the areas cleaned and prepped.
Now what can I use to replace this stuff?

I was thinking of using 1/2" double sided tape between the fender and the car and only sticking on one side. (no idea what to call that part of the car...)

Will that work?