Wrong. It is sort of a model issue, as it was only 750L's that came with hammock seats. All other Panda's came with the two peice rear seats which the shelf attaches to.
I had a J-reg with a hammock seat (it might have been around then that they phased them out), but mine could have been sitting stock and been registered later that other Panda's with the hammock seats.
Your 750's, what were they? 750'L's or 750'Mainias' or any of the other 750's?