Has anybody experiemented with spray on bedliner on fenders and ect? to prevent rock chips and salt damage?

I have used under coating on the inside of my fenders, and it is a bit of work but I live in canada and it works great. my 2002 dodge caravan has no rust on the fenders, i will do the same with my new dakota. but I have not tried it on the outside of the fender, there is a product to do that

Welcome to the site,
FF