It's the wood in between the metal half moon shaped tin that bolts to the floor and the box side, the metal arc that is in the picture I showed goes over the top of the wood.
OK, I missed that the last photo of John’s was a different truck. 38.
Wish we could see the inside view of the Jim Carter dually.
But the 38 doesn’t seem to show signs of the wood half moon having been capped with metal.
If you have those pieces like in your photo, I would hope you rebuild the wood part and cap it.
C
