The Mustang is a 65. The give-away is the engine code "C". That engine was not available in the 1964 1/2 time frame. The 64 1/2 engine codes were "U", "D", "F" and "K", 65 engine codes were "T", "C", "A" and "K". The other give-away is the scheduled build date, 20 H, which is August 20, 1964. Per the "Mustang Production Guide", the last documented 64 1/2 San Jose Mustang was built on July 31, 1964, the first 65 Mustang from San Jose was made on August 1, 1964. Early 65 cars used up parts from 64, the hoods and headlight buckets being two. There are others.
Jim