Tube sellers

Personally,I don't think its very likely that you will recieve many absolute NOS tube..How can one know ( unless they bought them new years ago ) ..if they have or have not been used..I do feel ( and have bought many NOS tubes )there are many relaible tubes sellers ( and dealers ) that test tubes and they test in the " NOS " area of testing parameters..Some tubes dealers have NOS tubes that are still in the Original boxes and test in the NOS area,so I suppose its possible that some are NOS..To me the most important info is how the tubes test and how quite they are..If they test in the NOS area and are quiet and to me thats ok...

Have to agree with Thorman.

As Thorman implies, most vintage tubes are more properly referred to as ANOS (almost new old stock.) No, I'm not joking. And I prefer ANOS when buying vintage tubes because they at least have some track record. If they were going to fail, they already did. If they were going to develop microphonics, they already have. Their test results are stable and won't suddenly change after a few hours, as is often the case with brand new tubes; either vintage or contemporary -- and which is why there's really no point in testing brand new tubes right out of the box. Most reputable tube sellers burn in new tubes for at least 24 hours before attempting to match them.
.