On top of the cosmetic effect the grille screen has a protective effect. It will keep bugs, rocks, shrubs and screwdrivers out of the radiator and the money for a new one in your pocket.
Wall Lathe for plaster (Galvanized, won't rust as easily)
Tin Snips (Angled ones work best)
Pliers or safety wire twist cutters
Start off by removing the 5 screws holding on the grille. There are four on top and one in the middle in the bottom part of the grille. Pull out via the top and lift out of the mounting holes.
Measure your lathe and cut a piece that roughly matches the opening for your grille + 2". Bend the lathe around the outside of your grille and fold it over in the corners.
Mark the places where the safety wire will connect the screen to the grille. Four spots ont he outside of the grille, two towards the center halves of the grille and one in the middle. Then remove the screen and set it aside. Drill small inconspicuous holes on the inner lip of the grille in the spots you marked.
Place the screen over the grille and secure it to the grille using the safety wire. after twisting the wire bend the twisted parts over so they wont catch on your arms if you ever need to feel behind the grille.
Cut your hole for the hood catch. Install the moulding around the hole so you don't make mincemeat out of your hands when you open the hood.
Install your grille with the new grillescreen onto your truck and view your handiwork. Confident that no rocks or shrubs will end your day early and expensively.