No not NOS! as in Nitrous, but N.O.S. as in New Old Stock. Dealing with old cars you see a lot of people abusing the NOS moniker. Ads like "NOS throttle body. Good condition and removed from running car..." See that? Its not a NOS part - its not NEW!!! It is a used part. It may be a good used part, but by adding "NOS" to the ad, they think that they can justify adding 20% to the price. No, NOS would be like the NOS group A 240 grille that I scored. It was in its original packaging and had the Volvo dealer tag on it. A pristine part, never installed.
So if you have a truly New Old Stock part, please feel free to use the NOS tag on your ad - and charge accordingly.
If you have used parts, just say so.