[ChevLoRay]

You're on the right page. Top unit is just the grille w/o the GMC letters. If you wanted to have a billet grille, the bottom one is for you. The center unit has just about everything you need to do the conversion you want to do, except for the panel between the grille and bumper.

As for the headlights, if you stay with your original glass quads, the grille fits around them w/o any probs and you don't have to worry about them turning yellow. The side markers are only lit on the lower section. The upper is just a reflector, so only having one light on each side is as it should be.

If you want the top grille, be aware that you still need the letters G M C unless you want to install a billet grille. If so, do it before you install it. The bottom of the later grille has a couple of clips that lock onto the panel I mentioned, in addition to the screws at the top of the ass'y.

Don't worry about the question. There's always someone on here who has an answer.