Can anyone tell me if this is the Late-2012 or the Early-2013? I found the same model at Amazon here and at the bottom of the screen it says "The base Apple computer model of this is an upgraded model was built upon was MD212LL/A." When I check the MD212LL/A at this site, it says the MD212XX/A is the Early-2013 model. If this model is an upgraded (from 128gb to 512gb) 2013 model, it really seems like a great deal. Am I missing something?