You cannot install 6.7 in CS6. It is specific for CS5.
If you are interested by the additional camera support, I suggest that you convert a copy of the files with the DNG converter 6.7 until Camera Raw will be updated.
If your camera manufacturer supported DNG as a native raw format, you would not have this issue. (And I can't imagine what the ACR/Lightroom and other teams would come with with the time they would win thanks to that.)