Is the tube seller dodgy?

[Quenya]

Hi. I'm a beginner with tubes. I'm looking at bidding on a Osram U50 tube described by the seller as "tested", though no test values are specified. When I asked the seller to clarify how the tube was tested, they responded that their tube tester can't test U50 so instead have to use an equivalent which in this case is CV1268, and the equivalent matched closely. But since it was tested as an equivalent, they state they didn't record the results in case the test results were slightly inaccurate. The tube is merely stated to test very good.

This is a seller with over 5k sold items, including many used tubes, and 100 % positive feedback.

So here's my newbie question: is their reply normal or a red flag?

 

[moriez]

Seller doesn't give the impression of being a lying sob but you still end up clueless as to what you're buying. On eBay etc I'd always go with that results are a must.