Could someone tell me the typical size of the tie down rail in the cargo area ? I'm referring to the 39-46 models but I think the later model size would be fine. I'm in the process of refinishing my interior and I would like to add the rail. The end connections and the the threaded segments in the ribs are there but my rig as originally equipped had eliminated the rail. I'm thinking it's approx 2 1/2 - 3 inches wide and approx 5/8 inch thick. Thanks.