That listing looks questionable - publication date is listed as 2007 and 6th edition is pictured. That's a good buy, even if they're the older ones!
I am hoping that Midway just did not update the description on the listing. I expect a copy in a day or so, if not an "8th" edition it will go back. If in fact an "8th" edition, I will follow up with any evident changes from the 7th edition.