I had one heck of a time trying to figure out how to get my CS6 swatches working for Illustrator CC in Mountain Lion. It completely escaped me that the folder I needed was in the hidden library files under users (a new thing that Mountain Lion does). Here were my steps:
Make hidden files visible:
http://www.tekhelper.com/showing-hidden-files-in-os-x-mountain-lion-10 -8/
Grab files in User-Defined (CS6):
USER/Library/Application Support/Adobe/Adobe Illustrator CS6/en_US/Swatches/
*user = your computer user
*en_US = your language
Copy all of the user defined swatches from this folder.
Place in CC folder:
USER/Library/Application Support/Adobe/Adobe Illustrator 17/en_US/Swatches/
Make hiddle files invisible:
http://www.tekhelper.com/showing-hidden-files-in-os-x-mountain-lion-10 -8/
Relaunch CC, and voila!
Hope this helps.