it is cheap plastic. my '05 bullet has few small cracks around the bolt holes too!!@@!!! anger...
i cleaned the plastic really good with alcohol and used a good quality super glue in the crack, then used a clear epoxy for around the ouside of the hole to give it a little for strength. it seems to be holding very well.
i have the soft copy of both the owners manual (.pdf) and the shop manual (.wps). i can email them if you would email me a copy of the new shop manual when it is out?