Im kinda confused as which model numbers are the newer rMBP. I dont plan on buying from the Apple store im gonna buy from the Navy Exchange since its around 100-200 cheaper plus no tax and extended warranty is way cheaper than apple care. But before i buy i just wanna make sure im buying the newest model that came out im thinking either the 13 inch high end or low end 15inch. When messing with the demos where do i go to see the model number