[3macs1]

All depends on how they were stored. I have NOS ones for my 70 chevelle that were purchased in the late 70's and they are just as nice as the day I bought them. No cracks dryness etc.They were in a bed room closet.The only NOS parts I can say I have had any trouble with is the plastic items that are not black and any part that originally had some foam on it.They both seem to break down no matter how you store them.
Just my experiences