Is there a specific reason why you want the diamond plate? Is it to cover damage? Is it for looks? Is it for protection?
The reason I ask is because the diamond plating doesn't do much for your vehicle as far as protection goes. Avalanche Engineering
has some corner guards that are designed to take a sledgehammer hit and not show the damage .. but they are not diamond plate .. they are smoothies for use on the big-rocks.
Damage covering is worse than fixing it right. There would endup being places for the dirt, water and such to work their way in, and cause some ugly amounts of rust and further damage to the point that you would end up needing to replace the tub with something from JP OffRoad
in Spokane (or something similar .. fiberglass, aluminum, kevlar, etc) ..
Hope this helps a bit ..