From what I've seen from Kawi's line up, no other of their bikes share our rear seat. But I could be wrong.
The part numbers are similar but no dice. It appears the z1000 and zx10r (and probably others) use two locking cones whereas the ninja uses a single bar locking mechanism. At least from what I can tell looking at photos (dealers are too far away)My suggestion is to use the rear seat part # and check other Kawi bikes for the same#. I doubt if they'd match though as the sub frames are different on most models. Thinking more, maybe the Z1000?