I believe the working title was Future Tank.  There couldn't have been more than 2 or 3 made under that name.  By the time we got to AMOA (Amusement and Music Operators Association - the main trade show) it had been given its final name (Battlezone).  At one time it looked like it was going to be called Moon Tank, so when I was told to put some vectors together for a planet, I looked in my Almanac and did a crude picture of the East coast of Australia.