In a 1953 1/2 ton, there is a sloping metal pan that connects to the frame under the radiator and comes forward to the bottom of the grille. I cannot find it in anyone's catalogue (ours is in not the best shape), but I also do not know what to call it. It looks like a baffle of some kind; I do know that it is not the "bumper apron," though. Maybe I could find it if I knew what to call it.