I have ML installed on my D630c.  The procedure worked well. 
  
However, I am having a problem with the App Store.  For some reason, it won't let me download some of my previously installed apps (I did a clean install so I don't know why it's not letting me).  Also, I cannot re-download the ML installer from the App Store.  It says that ML is not compatible with my system, which is obviously not the case since I am running 10.8.3.  Is this because my machine is listed as a Macbook 3.1 (which apparently is not supported).   
  
If so, could this be problem with the machine identifier in the plist file? 
  
EDIT:  Apparently this is a problem with ML itself: http://apple.stackexchange.com/questions/84760/cant-download-mountain-lion-from-app-store-on-a-mac-already-running-mountain-li