You are a wise man , otherwise I'de have a great job but I know you wouldn't take a free ticket to the show if I came to your town!! Need more emoticons - almost reminds me of reading Insiders messages although I don't think he ever used that many!! This can go nowhere fast - I'm done!!
It hasn't exactly fallen off the side, but I'd call this a little more than "slightly" off center. I think it's a far more interesting coin than you've heard so far. Lettering has actually fallen off the edge of the reverse - the popularly-accepted dividing line at which value begins going up - and since the obverse isn't that far off (although the TY are very near the edge, and if I have it right they're normally closer to the rim than the reverse lettering) one has to think the dies were misaligned as well. There are a few different failure modes which can create this look. Is there any reeding at all around the edge of the coin? And how does it compare stacked on a "good" Kennedy? Not a "Million Dollar Coin," but I bet anyone with a scholarly interest in misaligned dies and off-center strikes would want to see it. I think @cladking is a good member to invoke as a start point for more information - he should know someone with such scholarly interest if it's not in his wheelhouse - as Kennedys aren't exactly my specialty and I don't know how rare such strike errors are with them. Let's see what we can stir up for you.
I think its a combination of die misalignment with a slight off center strike. I think he could get $5.00 for it which is a whole lot better than .50 cents. If it were mine, I'd 2x2 it up and put it away.
This could be a valuable coin to the right error collector but such things often sell for only a few dollars. Sorry I can't help more but errors are mostly outside my knowledge.
Sorry for "invoking" you, but you are the first person I think of when any viable discussion happens about coins of this era. You're a victim of your own (deserved) reputation.