Pics of your 3rd gen
#127
!) does it have stiff suspension? 2) If so does the rear end have a lots of extra links on it? The reason I am asking this is to only help determine. But even std coupes could be gotten with F41 or higher suspension probably, I have had a few and they handle very well. There must be something decoding from the vin number maybe? Is it a 5 speed manual. are all the z emblems present? I.E. inside the car's interior all decals, labels, z28 stripe package? seat and interior logo's etc. Code the rear end maybe? Hope this helps I don't really know actually.