I just got word that the composer of Battlezone 2:

Carey James Music (http://careyjamesmusic.com/)

Has released the BGM along with left out tracks here:

Battlezone II patch 1.3.6.1 Public Beta, Music (http://www.matesfamily.org/bz2/)

It's about 176MB, I downloaded it and it's the real thing, go grab!

Good find, this. This just reminds me that Activision has in my opinion neglected this portion of the series...

Thanks for the heads up!