Few c10 questions for the wise...

[Westcoastpainter]

Hey Guys,
New to the site, im a c10 guy who just picked up a project.. so i have a couple easy questions if anyone could help a guy out. Thanks in advance!

ok so im building a 70gmc swb 2 wheel drive p/u. it came with three extra fenders two or three are chevy. How can i tell the difference between chev and gmc? Im guessing the bodylines in the front of the fender are different for the chev grill on the chevys. so I want to put a 71 chev grill in it, honeycomb one with the blue bowtie... i have gmc grill and fenders on it now, so for the transition im guessing i will need chevy rad support and fenders to put in the 71 grill? Are the 71 chev fenders specific? Can i use my gmc rad support or since its four headlights it wont work with the chevy set up? sorry for the rookie questions!