I have also never heard about red recessed ignition key for sandy production. Just look at original photos of late preproduction bikes. There is NO red plug !!!
Strange is, that this red plug is on the Ebay after the Pre Production bike was on Ebay. Sandcasts were not only Honda models with the recessed ignition switch, but Sandcasts had no red plug from the factory. Just donīt be silly to believe everybody. So I can tomorrow say, that some Sandcasts had yellow starter button. Everybody wants just to earn some money on Sandy myth.