You are north of NYC and should be able to find an audio service company that would test these for you. Audio Classics comes to mind.
WE 300B tubes
Not sure if this is the place, but I have (4) Western Electric 300B tubes. My dad was an amp design guy ( Ted Hammond from NYAL). I would like to sell them but I don’t know how to go about it as they are not tested- obviously I am aware of their value if they’re in good working condition.
Thanks