You'll need to track down the Nissan chassis number to run it through FAST. It should be physically stamped into the chassis somewhere. Newer Nissans have it on the right hand chassis rail near the RHF wheel. Not sure about older ones though. I'm not sure on the legalities of not having a manufacturers build plate attached to the car, but it might be worth looking into to save trouble down the line.
See attached. Doesn't appear to be a V-Spec.