How to Identify a GM/NOS Hood?

[Graham57a]

My dad recently acquired a 68 chevy c10 that came with a spare hood. The truck has been sitting for about 20 years and it came with a handful of NOS parts including a tailgate, outer rockers, and some smalls. He said the bottom of the hood has been painted but the top is in black DTM primer.
My question for you all is "How can you identify a GM hood without the NOS sticker or a box?" One of the strange things I noticed was that there was obviously a sticker on the underside of the hood when someone painted it because they since removed the sticker and you can see exactly where it was. It also does not have any holes in the front of the hood for the Chevrolet emblems. This would make sense if the part number is the same for a 67-8 chevy hood and a 67-8 gmc hood.

Any input is appreciated,