Posted Wed Jun 13, 2012 7:46 AM
I do have a theory for that.
The Atari arcade games from which 2600 Combat was derived from were all part of the "Tank series" and they range from 1974 through 1976. (well from Atari and/or Kee Games anyway) And the last one "Tank 8" is from 1976. Perhaps Sears was giving proper copyright to the original copyright year and/or holder.