Is the Sonar Command Center ignorant of what I already have installed from prior versions of Sonar?
 
Seems "dumb" that I have to figure out what is "new" component, and what was already installed from prior versions X1, X2, x3, etc).

The Command Center only keeps track of what it installs.

Here is a discussion about the next release of the Command Center http://forum.cakewalk.com/FindPost/3213876

Be aware though that the "Boutique FX" have apparently been updated. So even though you likely have those plugins apparently they have had some fixes done to them. Not sure WHAT they fixed but yeah... they've been updated somehow so they will show as new content since the last release or so (forget whether it was Everett or Dorchester that happened).
 
Edit... and I would not have known that if it weren't for scook's posts on the matter.

scook
The Command Center only keeps track of what it installs.

The other part of this comment to realize, is that if you manually install, CCC does not know it is installed either. The update should (hopefully) address this.