Gen-1 might be considered original '83-85 Gpz-250?
Gen-2 is '86-87 models we finally got here.
1988-2007 models are typically called pre-gens and 2008-2012 are new-gens.
You can assemble bodywork piece by piece with used parts from fleabay, but that can get costly for entire set.
Only supplier of new bodywork for pre-gens are these guys:
http://www.airtech-streamlining.com/...2501988-06.htm