Well a body repair manual would show the diagram of how everything goes together and what it is called. The only way you’ll know what for sure is damaged is if you do a disassembly first. For sure you’ll need the upper and lower parts and maybe whatever is behind it and some fasteners. Best thing is to go to a GM dealer site with the diagrams and take a look to get an idea. A place like gmpartsdirect etc. should have the diagrams and the prices that you can order from. Or if you are looking for used, you can go to car-part.com for a regional or nation-wide search.
Of course the other thing you can do is go get an estimate from a body shop and they will list the parts that they need. Of course it may not be a complete list because they won’t know for sure until they pull it apart either.