... Looking back at old photos of the bed I can say that somewhere along our trucks prior life the side angle strips did not extend over the rear sill (ref tailgate.) I've compared how these angle strips sit in relation to the forward bed panel sill and it appears that the gap between the edge of the angle strip and the forward panel skin is approximately like your configuration.
I can confirm that Kevin's bedside angle strips extending over the rear sill of the tailgate is, in fact, the way it left the factory. It is extremely unlikely that the angle strips on your truck (Texas) ever stopped before the sill.
My truck still has its original bed installed and the angle strips sit on top of the sill.
