Yes and no. They do bolt on however the rotors are larger on the 2008+ bikes. You have 300mm and 08+ have 310mm. Also, you will need to mill off atleast 5mm of material from the calipers so they sit far enough down on the 310mm rotors(the fork mounts for calipers are shorter on 08+). Or buy 320mm rotors and then the 08+ calipers will work fine.
You CAN use the 08+ calipers but HAVE to use at least 310mm rotors off the later 08+ bikes too. The pads will not completely touch rotors though but won't be noticeable evn if track riding. Will cause a little lip to develop on pads. That is why 5-10mm should be milled off calipers though.
I don't know about that
Kawasaki had a habit of just making the caliper mount point different lengths from the axel.
i upgraded the disc's on my 04 with 06 and had to put 10mm spacers and longer bolts
because the fork mounting point was shorter on my 04
so just changing calipers may be a bolt on and off thing.
I put 08 calipers(same as gen 4) on my 05 zx6r. Too get it to work I got 08 discs. I thought that would work and I wouldn't have to do anything else, wrong. I had to have the caliper legs cnc'd 2-3mm (forget the number) to fit perfectly. The guy that did it for me still has the rig to do it. You would have to mail them too him and pay for the machining. It would probably be way cheaper to just get the nissin calipers.