My cousin is looking to buy a 20" iMac and I have been searching for the best deal for him. I came across this iMac which sounds perfect. http://www.jr.com/apple/pe/APP_MB391LL_SL_A/ However, when I look up the model number (MB391LL/A) I can't seem to find it ever existing in Apple's specs database. Anyone know why this might be? Where did this model number come from? It has the same specs as the mid range 2008 iMac, but that iMac's model number is supposed to be MB324LL/A.