Not even close. ZZR250 has aluminium perimeter frame. EX250 has steel backbone frame. Look at the holes where the bodywork mounts to frame and they don't line up. You can always weld brackets to EX250 frame to hold ZZR250 bodywork. Heck you can fit any body you want that way.
Check this out for pre-gen EX250 bodywork
http://www.airtech-streamlining.com/...2501988-06.htm