yeah I would agree it is suspicious except for the fact the owner has a bock custom mic out of 47 parts, knows David and is legit in the music industry. Anyway
I traced the pinout to the following
1 audio +
2. audio -
3. pattern select
4 Heaters +(DC)
5.B+
6.GND
I currently have it hooked up to a supply we had in the shop that was a 7 pin prototype for a tube mic and made a 7 pin to 6 pin cable. The 7 pin had redundant ground pins. Anyway it's working so not really needed after all.