I coated my '49 running boards with Rhinoliner, and they turned out great. No wear at all, and best of all it hides all the (little) dents so you dont have to try to body putty them all.
*i did all this with brush on Rhinoliner*
Brian K
p.s. i also Rhinolinered the inside of my bed (not the wood or strips), and the front splash pan. All worked out wonderfully, and i would suggest this to anyone not going for 100% original.