Scott, in Eclipse, go to install software and in that dialog there is a link in the bottom right corner 'What is already installed'
Can you see the installed software, on that dialog, you have a number of tabs that will give you much information.
CDT is the C/C++ Development Tools.
You only really need the Eclipse IDE and the CDP addon and then Jan's extension for it to work.
The link you provided was for the CDT 32 bit package for OSX, so as far as I understand that is correct.
I did this within Eclipse though, selecting from the available package list and letting it install it.
I run on Eclipse on OSX 10.6.8
Eclipse version 4.3.0, Build id 120120810-1300 from Eclipse preference, where you can also see a button for 'Installation Details'
C/C++ Development Tools 8.1.2.x
Jan's Eclipse Arduino extension 2.0.0.18
_____
Paul