NOS is not necessarly a great deal------Even new take off's can be a problem. Bought two 71 trucks 2 years ago advertised as having a new take off tailgate. It was true but as "bagged" says "sometimes they are stored in damp locations".
This new takeoff was stored in a garage for 32 years and the front/back was nice so I didn't check it too close. When I started loading, the drivers side-end, which was sitting on the concrete was rusted thrugh!! Ugh!!!
NEVER trust a description without personally checking it out with your good glasses on, using a magnet for bondo, etc. And get the seller's agreement if the description doesn't match the item, they will take it back and refund you money. Huck