Well, as to the exact reason was for making it, I'm not certain-- but it's possible it was created for the Armed Forces Network. Film copies were required for circulation to the overseas troops, and they were still routinely being made in that time period.
And it's actually been offered a couple of times before, but in truth, I'm not so much of an NTT fan, and even though I'm an archivist, I can't get too worked up about an episode that almost certainly exists on a video master, but is being allowed to gather dust because of music clearance issues.
So, that's why I haven't taken it off the market myself...
-Kevin