s Guide to Authenticity II takes a part-by-part, year-by-year approach to what an owner or prospective buyer should look for when evaluating a 911 or 912 Porsche. For each year, from 1965 through 1973, the author examines every change, documented or not, of each model - and now including major mechanical components. Included are the most accurate and comprehensive chassis number and color/upholstery listings anywhere.