what about the last two letters i know they stand for revisions
Where does that information come from?
This is not true at all, the last two letters can be a completely different product. Hell, there are ECU's for different engines where only the last letters are different.
Can i flash this onto a car thats 1 year old same ecu number just diffrent ending letters like mine is CG and the other is CF
Maybe. Better be able to recover it in boot mode though.