Can you tell which engine option your 1966 Corvette originally came with from the ID or Trim plate?

No, the 1966 Corvette's trim tag (commonly called an ID plate) does *not* specify the engine option. The trim tag provides information about the car's body style, paint color, interior color, and other features, but the engine is listed separately, often on a separate data plate located on the driver's side of the dashboard or sometimes under the hood. You'll need to find that separate documentation (if it still exists) or consult other records to determine the original engine.