Rick - The below picture is copied from the GM Heritage
1946 Chevrolet Truck PDF. Drawing and lower description info provides the original Chevy finishes for your 1946 "upper grille".
The original piece is listed as Polished chrome plate with "Red" Baking Dulux paint for the letter and line recesses. As you said, the choice is yours, but if you are going for a "Concourse d' Elegance" show event, judging will include this level of detail.
Lots of info in the GM Heritage file to help you pre-inspect/self-judge your truck to help you show off your truck if that's what you decide to do.
