I guess my point was will it be sealed better with paint and liner.
I know that the primer I am using is not a sealer, when I was applying the primer there are two tight places between the front of the box and the inner fenders as I took 15 inches off the bed, there is around 3/4 inches room max, when I stuck the paint gun in there and pulled the trigger the primer just shot back at me instead of going on the metal, I had to soak it just to get it to stick, I suspect the paint will do the same thing.
The liner would likely be rolled/brushed on and will be thicker but not uniform either, but in the end I need to buy more paint anyway, so maybe I should just paint the shit out of the inside of the box, it will likely look better that way anyway, I just changed my mind again.
Oh, the sides of the box look way better now, and I decided to fill a trailer hitch tow plug hole in the bottom rail below the tailgate, so I will likely only get that done and some parts primed I cleaned this afternoon, so Saturday or Sunday will likely be paint day, I have a morning job and I need more paint so I will not likely have time to do any painting tomorrow.