If you could post the vin that would be great. You could look at the 1990 page in the VIN Project on the main site to see if you VIN is on the list. If you find it, see if any of the others in the same group are blue. Click and see if it's a WSP car as well.
Do you have the door tag? Is it readable? The DSO around the lower right corner(6 digit # I believe) can also help in determining previous service history.
For absolute verification, check to see if the buck tags are on the radiator support. They should be on the drivers side, down behind the headlight, right above the bumper shock. If there are two, one will have codes for the build of the car from the factory, and the other will have the agency it was intended for.
Hope this helps
