Isn't the keyboard the dock? Hence, it comes with a dock. That is what the title of the link seems to indicate.
Yes, the keyboard is the same as the dock and Asus/Engadget are reporting that it is included at $600. However, if you look at the Staples ad, it shows the dock as a $170 additional item, and the listing here [staples.com]
also indicates that the keyboard dock is sold separately.