You've got me curious now. I just asked the seller: "Looks like one that our family had when I was a kid. Question: Are the Z and Y really switched around on the whole machine, or are the keyboard keys in the wrong spots?"
I got an answer from the seller:
"Wow, that is very observant. I did not notice that! The keys have not been switched. I see that when I press each key the correct letter comes up. Thanks for pointing that out!"
The one in our house had the usual QWERTY keys. My guess is that somebody has tampered with the eBay Olympia and moved things around somewhere along the line. The Olympias pictured at http://www.mrmartinweb.com/type.htm#olympia are all QWERTYs.