is single light per side then you need : core suport / all headlight parts / and all 3 grill sections.
gmc grills are chevy grills do NOT swap around with headlight buckets. chevy is all chevy and gmc is all gmc. 2 diffrent shapes is why. but thay both go in the core suport.
also need pigtails for headlights and turn signals.
now a good source for the center part of the grill is the chevy/gmc vans with same body style 4 headlight. just the center swaps NOT the headlight bezels. all the pigtails and light parts can be used from the van . but not sure on turn/marker lens assembly tho. and the upper 5 tabs on the van grill will be deeper in than the truck grill. just got to drill 5 new little holes for the screws.
the core suport is 89-91 and 81-87 body parts fit this . no special fendors needed. i shipped a core support 1 time trew fedex no problems. just wraped most in cardboard and then shrink wraped the whole thing. slap on the tag and go.
hope this helps you.