Yes, Brf and other posters are correct... The pairs you see listed on Audiogon right now are NOT true "bad boys". They are standard 2-hole Sylvanias, worth far less than his asking price.
I have spent countless years listening to different brands and versions of 6SN7s in various components, and have found the older Sylvania 6SN7GTA, WGTA, and GTB's sound a bit more forward and less refined than the "bad boy" versions, which have more warmth with a richer and sweeter sound. The older green label GTB's have good dynamics and bass punch, and the tall bottle green label GTB's (hard to find), are quite good. Sylvania also made some short bottle, top gettered, "slanted" chrome dome 6SN7's back in the 1950's that had shiny, black, 3-hole plates. These true "chrome domes" sounded excellent, and very similar to the "bad boy" versions. The sonic differences are quite easy to hear and appreciate.
I have spent countless years listening to different brands and versions of 6SN7s in various components, and have found the older Sylvania 6SN7GTA, WGTA, and GTB's sound a bit more forward and less refined than the "bad boy" versions, which have more warmth with a richer and sweeter sound. The older green label GTB's have good dynamics and bass punch, and the tall bottle green label GTB's (hard to find), are quite good. Sylvania also made some short bottle, top gettered, "slanted" chrome dome 6SN7's back in the 1950's that had shiny, black, 3-hole plates. These true "chrome domes" sounded excellent, and very similar to the "bad boy" versions. The sonic differences are quite easy to hear and appreciate.