6922 Amperex PQ White label... D or O-getter? Holland or Hicksville?

I don't think the 7308 is mil spec. It's heater is rated at 7V while the 6922, 6DJ8 is 6.3 volts.

Oh yeah, D vs. O-getter. The D getter is in the earlier construction of these tubes and is said to be superior. I have D-getters since my tubes are from the 1950s, so I can't speak to the difference. 

The same can be said of small O getters vs. large. I do have some experience here; large O getters are superior, perhaps they create a greater flash and a better vacuum.

I have a pair of these:   https://www.audiogon.com/listings/tubes-amperex-7308-usn-cep-pq-matched-pair-test-nos-made-in-usa-gold-pin-2014-02-15-accessories-92821-brea-ca, from 1962 and '63(still identical construction), that are just sitting in a drawer.     You’re welcome to try them, no strings.    Just sanitize and UPS them back, after listening/auditioning.     PM me, if interested.

Wow @rodman99999 , that's the good stuff. These are mil spec matched with tight tolerances.

They do perform beautifully.    Just a little too warm, for my tastes.     To me; the grey shield, early '60's, Siemens CCa, is joy in my BAT VK-D5.