I'm not saying in bed fillers are wrong, just that there are alternatives. If gas is so hard on paint then every motorcycle gas tank must be damaged because that is where the pop up cap filler comes from.
You know when you posted that, I was thinking a plate in the bed and not the license plate. I know, “reading is fundamental”. That would be slick on your ‘59 Apache. Not so much for a pre ‘54 AD.[/quote]
I suppose I should have stated "Flip Down License Plate". There is a pretty good thread on this on the H.A.M.B., your right of course that it works better with a Task Force truck.
With a fleet side there are more in bed options. I used the original in-cab filler neck with grommet and welded a panel into the bedside to hold it. A short elbow piece of exhaust tubing connects to the tank between the frame rails. No damage from gas spilling on the paint and I have spilled on many occasions.