The KZ550 & KZ650-CSR cast alloy wheels don't have those inner ridges & Tubeless is cast into them. They look like the wheel in the second photo. The diagrams at Kawasaki.com don't show tubes for those models. The factory manual for the CSR has a warning that tubes should not be installed on tubeless wheels (in the case of the rear wheel, since there are no rim stoppers, the tube's air valve has a greater chance of getting damaged if the tire spins on the rim for whatever reason).
Edit: upon closer inspection months later, the 440/550/650 cast alloy wheels have a small ridge - it's not much, though.
