How have you confirmed that's the accurate one, other than wanting it to be? Far easier to swap the buildplate on the cowl than the vin inside the dash. Perhaps they've both been swapped or both are still accurate and original to what they are fastened to now. Do the engine numbers match anything? Stamped number on the trans? Numbers on door decal match anything? Original paperwork or buildsheet? Stamped numbers hidden behind the heater/AC box match anything or say? Half of these even if they still exist can easily be swapped in the last 45 years, but if they do exist and match the existing VIN or each other, tells you something. Repainting a car blue is far easier than what you'll need to do, and the value will remain as a parts car.
Ok possibly already checked the firewall stamping and matched it to something. Although I doubt that will help in anything much. Perhaps add some pics. Are both Norwood plates? Is that where it says WS4 and the only thing we are going off? How do you know the cowl plate is original if the stamped numbers match the VIN and not the body number?
You'll need far more information to give them and still be knocked back than what you are providing us.