According to a Ford press release from its launch, the Mustang Mach III Concept was designed to "blend the styling cues of the classic Mustang with Ford's state-of-the-art design and technology." ...

This being the case, you may be interested to know that the first Mustang of 1964.5 wasn't actually the first Mustang at all, being preceded by a concept car that made its public debut in 1962.