A frequent but good question and why you need to read the book! All kidding aside, from 67-72 St Louis used the Corvette Order Copy on the gas tank to document options. This study and collection of buildsheets began with 1973 when GMAD took over management of the plant from the Chevrolet Motor Division and introduced the GMAD landscape style manifest. The first chapter describes this in great detail and Chapter 2 describes the GMAD manifest with numerous color illustrations.