ok so i dont have any rust by rockers should i rhino line under the doors and rockers?

 

As long as there's no rust there now putting a coating like that on will help prevent the chips and nicks that let rust get a foothold. I think it's a good idea.
I used NAPA truck bed lining on my rockers when I re-did them.
I'm iffy about doing it once the rust has already started, it tends to accelerate the rusting underneath the coating where you can't see it.

 

Look up line-x they have a body armor spray on that's not was thick as the bed liner but still as strong.