You can enlarge the holes on the the MG footpeg bracket, but it is not advisable, as you may not like the set-up (a strong possibility), and wish to return to stock. The more flexable option is to make 2 bushings (11mm OD x 6mm ID x 22 mm L) and use the MG pins with the Buell pegs and springs. You will have to remove material from the forward side of the tabs of the Buell pegs until you get a nice sliding fit into the MG bracket. If you get sloppy on the fits you will be disappointed, because the pegs will not feel as solid as the originals. I used bushings made out of tubing that was "close-enough" in size and ended up doing it again with proper sized bushings.
The bigger problem is getting the gear and brake levers positioned properly and I'm still experimenting with that.
KenM