Build dates

New models was introduced around 23rd to 27th of September each year. The last years production ended Friday the third week of July. In your case you have an early one. Your model wasn't introduced yet! However the production started the first week of August as @65 Dartman mentioned.
Interesting facts, thanks for the help everyone. Its funny you say that the model had not been introduced yet. Ive always wondered about if this was some sort of demo car as it was not an ordered car but has buckets and a console from the factory along with the A.m. radio and bumper guards. 273 and auto trans option, It also got the blue top which I have not seen many of. Odd for a non ordered car.