Once painted black they are no longer NOS. They are used. (eye of the beholder thing
)
If they have paint and are clean, $500.00 each if as good as a NOS fender. If the fender is never been bolted on and you can prove it is straight, possibly more. I paid $300 off of here a couple of years ago for a 72' Demon fender with (not knowing) filler under the paint. It again is dependent on supply and demand. Only problem is right now the supply is low and the demand is high, but getting people with money to buy them is a differnet story.