I really don't think so. The earliest amps Evans was involved with were Sho-Bud amps, and I think that was probably mid-sixties. The amp in the photo looks a lot like a modern Evans amp, even including the tilt back-thing those amps have. Also, even if Evans amps existed already in '64, what are the chances of one being in the UK? It would also suck pretty bad as a blues amp - Evans amps are designed for clean pedal steel amplification. Sorry to add to the mystery. Which to me is now "why on earth would anybody photoshop an Evans amp into that picture?!?"