It is true that early production Norwood built '69s do not have X codes. No LA-built 69 ever had them. That makes it easy to clone a Z/28 from either. So beware. If significant money is involved I strongly recommend that you hire someone knowledgeable to examine the car PRIOR to purchase. The stuff everyone will tell you to look for [12 bolt axle, power front discs, dual exhaust] was standard equipement on every '69 Camaro SS and optional on any 8 cylinder Camaro.
Last resort: take lots of pics, post the link here.