100% sure of that. It didn't work with very many games. I know because i had Star Strike in Intellivision and played it using this adapter on my 2600. It's possible it wasn't an official product, but my parents were the ones buying the video games back then. I just know for a fact it worked that way because I kept the stupid thing looooooooooooooong after we got rid of our Intellivision but we always, still do today, had an Atari 2600.
That is an interesting little gadget UB, but that was not what I had. Actually it wasn't an adapter that plugged into the system, it was just an extension on the carts themselves. It didn't work with all games because some games had different connections. It's hard to explain I wish I could find a pic of it.