True, there is much inconsistency in the 'model year" designation in state titles, dealer invoices, service manuals, owners manuals, and brochures. I defer to the VIN plate designation as the standard for month and year. (I do confirm that the stamped engine number and frame number match the VIN plate. I know anything can be forged, but due diligence and care are required when representing a vehicle....especially to other Datsun owners.!!!)