Are All NOS Parts Created Equal?

[bbbentley]

Apologies for trying to be clever with title.
Here is what I would like feed back on: This question is primarily regarding 69 Camaro sheet metal. I have read that NOS is not stamped as well as assembly line pieces. I understand it was because of dies that were at the end of their life. A lot of the sheet metal was made all the way up into the 1990 s. Labels on the newer stuff has a barcode.

Are old NOS sheet metal that has the old part number tags, say pre '82 more valuable than their newer counter parts? If a fella has quarters or fenders, etc...perhaps even from the 70s, how does the pricing compare to a bar code label piece? Or, is there even a difference in quality or price? What affects NOS sheet metal value?