Franco,
I think there were three configurations.
Most common is just a shelf area; this is in standard cars with the soft top.
Then there is a "kinder seat" option, which is a sideways seat (back on the right side of the space) which is sometimes fitted to this standard area.
Finally there is the California Coupe; w/o a soft top compartment, this space is a bit larger. I've seen upholstered bench seat of sorts (not a whole lot of leg room even for a child) in that space
Any other, I'm not sure about...