The mac installer seems to be missing on that link. I did find this note at Adobe's site....
Why does a certain spot color from Pantone Plus series in CS6 appear different from same spot color in CS5 and older versions?
In CS5 and earlier versions, which included the older versions of the Pantone color books, most spot colors from Pantone had two definitions - Lab and CMYK. In addition, the default setting of the Spot Options dialog was CMYK. CMYK values took priority over Lab values. The spot color added to the document usually came with CMYK values.
In CS6, with the introduction of the Pantone Plus Series color books, there is only one definition for all spot colors. These definitions are in Lab values. So, it is a likely that a particular spot color from Pantone can appear different in CS5 (and earlier) than how it appears in CS6.
Workaround If it's necessary that the same spot colors are identical in CS5 (and earlier) and CS6, you can replace the Pantone Plus Series ® with the older Pantone color books. See Workaround 1 below. It's also necessary to change setting of the Spot Color dialog of the CS6 document to use CMYK values from the manufacturer's process books. These two steps make the Pantone spot color uniform across different versions of Illustrator. However, it could impact cross product workflows with InDesign and Photoshop, if you are using the new Pantone Plus Series ® with these applications.