Nice truck, welcome to the forum.
Pressed on backing plates, truly a 63.
The heater block off plates would indicate that the truck could have been equipped with the Economy Type Heater that mounted under the dash inside of the cab.
The white painted insert of the door panel would option the Custom Appearance Option Z61 and Custom Chrome Z62 would explain the front bumper and Aluminum Anodized Grille.
I'm going to say on your trim plate located on the drivers side kick panel PAINT #516 or 544 two tone. Red, Cardinal
You'll find that every 63 grille you find will be missing one or both headlight bezels.