Um, guys, not to burst your bubble or anything, but yes this IS what the internet is for.
If you do some searches, I'm sure you'll find a number of sites that show you which pieces are "impossible" to find. Yes, 2 out of the 3 are everywhere, it's the 1 magic piece that is the winner. And of course McDonalds knows that there's a 90% chance that every person who finds that magic piece will think it's garbage, and toss it away with their leftover fries.