Keep in mind that GM Canada Vintage services ended up w/ the files for many of the '77 and up F-bodys regardless of where built and shipped to new..
For all it costs, it may be worth hooking up w/ Geo. and the boys to see if you can document the car's original pedigree?.
http://www.gm.ca/gm/english/shopping/parts/vintage
Good luck!.
~ Pete