I think you will find the main difference is the mount for the rear master cylinder. The MC21 and MC28 M/C's are a different pitch. I believe the steps will interchange though.
My best guess is to get them, and you will probably find you either need to fit an MC28 rar master cylinder, or slot the mounting holes slightly to fit the MC21 cylinder.
Here's an idea... why don't you get them, and tell us?!
_________________
Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
Check us out on Facebook! Please "like" our page!