The 500 series tails have the original airbus interior that you see of a vast majority of the 320's they have the square plastic overhead bin latch covers (the gray thing you lift to open the bin) as seen below. The 500 and 600 series have different OHBs but the seats and the TV housings are all the same as seen in the 600 picture. The ONLY difference between the 500 and 600 planes are the OHBs.


The 600 series tails have an updated over head bin latch over that is more silver and elongated oval as seen below shaped

The 700 and 800 series have this interior with the new seats and TV Remotes. The 800 series planes are the only ones that have the airbags on the seat belts and those are only in the exit rows and row 1



The entire 320 fleet will begin to be retrofitted with the 321 interior sometime in 2014 so the look across the fleet will be the same