The PAIR block off plates for 2007 and EARLIER Hayabusa fit the GS. See ebay, and I recommend the ones without the o-ring. You get 4, so split the cost with a friend. Your original gaskets will probably be in one piece either stuck to the head or the PAIR tube. Usually can be saved, or buy new, or use high temp RTV. See pic below:
http://i51.photobucket.com/albums/f359/rkjjeep/PAIR.jpg