Show me a double-blind study where the listeners can hear identical guitars, through identical equipment and identify the body, neck, fretboard, whether it's a drop-top (and if so, what woods are used), etc. then I'll give the myth some credence.
Then, we'll get the same folks to listen to differently made guitars, through different gear, and see if they can identify the woods.
Then, we'll test the "cut under a full moon" myth.