Hey guys, for the record, I'm not actually following the thread today due to being under the weather. However, I am passing this information on from TubeMonger because they are genuinely trying to be helpful to us. Here you go:
"Did not mean to be curt. Shall write list of tips to id tubes for the board later today.
Mercedesman is an honest and upfront seller. He offers great values in desirable tubes. It is likely he was duped in this instance. He may not be familiar with the nuances of the various fakes coming out of former Czechoslovakia. Good news is that tube in question are genuine Tesla ECC88 tubes."
Hope this helps...
Hope you are able to get a lot of rest. Get well soon!
Maybe since I am new at this and I don't understand what "for the board" means... It is so nice of them to help out and create a helpful guide. Would love to get a link once it is up.