I have an antique metal cooler and likewise have considered how to secure items in the bed. I think possibly substituting a couple of eyebolts for the plank bolts along with bungees/straps might work. However, you will need to have something under the metal cooler to prevent scratching the finished bed wood. You will also have have unsightly bolts or fasteners in the bed floor…and Murphy’s Law awaits every opportunity for something to come loose. My solution has been to always carry the metal cooler inside, in the passenger side floor secured with a long bungee attached to the seat frame. For car shows, the only items I carry in the bed are my canopy and folding chairs, (bundled together) and these are inside soft padded bags. That’s a beautiful truck you have, - you don’t want to take a chance with that paint & bed finish!
