Originally Posted by evanb

SZX and SZY were the first two of twelve of SA's A320s that SA operate. They were not part of the original order from Airbus and came via leases from BOC more than a year before the Airbus order. The new A320 layout and seats came with the ten aircraft ordered directly from Airbus (SZA-J)

I am not sure what the current layout is, or what the seats are though.