Right after listening to this episode I happened to be in the Boston area, so I stopped in a retro video game store - Replay'd. It was a nice store, and they certainly had a better inventory of Atari games than my regular haunt. I was looking through the 2600 section, and sure enough: there it was! Polaris! After singing a few bars of Volare in my head, I debated whether to pick it up or not.
Unfortunately, it was little more than I wanted to spend that day, so I ended up with Sub Scan instead. Now, of course, I have second thoughts on that opinion.