The grille, while familiar (don't have time to research it right now) is from a car between 1959 and 1964. It's one side of a matched pair. Prior to 1958, pretty much no cars had 4 headlights. After '64, this type of grille material and dtailing was no longer used, except on some Soviet Bloc cars and trucks.
The hard part is the distance between the lights. On most cars with 4 headlights, the distance between the lights is no more than the width of one of the lights, if that much.
The '59 Olds is almost this wide, but uses a different shape housing:
The '60 Mercury is also almost this wide but the grille is one shape all the way across the car:
The detailing and shape of the bezels says GM to me, but it doesn't really match anything I know.
I DO know it is not off a car that only has 2 headlights, and it is NOT a centrally mounted grille, as the headlights are angled assymetrically.
be off a truck...
Hmm. I like good puzzles.