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.
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