I think this is what your are looking for.
Chrysler 300/300C Chrome Factory Grille Overlay: U.S. SPEED
Removing and reinstalling the stock grille is very easy. The only hard part is dealing with the 4 screws along the bottom of the grille. But these 4 screws can be left off and are not required because there are plenty of other screws and clips holding the grille on the car.
If you want a better quality all chrome grille then get the Heritage Edition grille.