We actually did to tests. The first was on a B&K tube tester, set at a sensitivity of 53 - which was the spec for the machine for an EL34. All of the tubes tested out between 95 and 110, with two of them a little low at 85. Then we did a sine wave test for noise with an attached meter for output. Using a baseline control we got 21 watts in push-pull per pair of tubes - any combination of any of the dozen, even the two low ones (although I confess, I do not know the plate voltage). The sine wave - control at the bottom of the wave, and tested tube at the top - revealed no noise in any of the tubes.
The guy that did the test has been doing this for forty years - a really cool shop btw - and his opinion was that not only were the tubes still good, but they showed remarkably little wear at all.