47-53 Chevy Grille installation: There should be 3 'captured' or nut inserts on each vertical side piece of the grille. The bolts are installed from the inside of the inner fenders.
If the 'nut inserts' are missing you can use nylock nuts and washers. There are a bunch of screws that go thru the bottom of the lower baffle pan that install thru clips that are installed on the bottom grille bar. Lastly there are 2 screws that are installed on each side of the top grille bar above the parklight assemblies. They are installed thru clips that are placed on the top grille bar. The upper hood latch baffle pan most be removed to install the 2 screws on each side of the top grille bar. Note: I have found that stress cracks appear on the top grille bar at the front corner areas where the hood meets the fender. Don't tighten the 2 top screws on each side too tightly - or leave them out. Lastly install the upper baffle pan, with bolts that install at the upper radiator support , bolts that install into the vertical grille braces and bolts or screws that install thru some clips that are in the top grille bar center area. My personal experience with 4 of these trucks. Good luck.