Oh boy, that was it. Thanks so much for the help.
I think your answer is that true and false are not strings and therefore not quoted. Numbers are not quoted, along with boolean.Very subtle at times .
this is what I send and it works fine, notice the false is not quoted.:
{"request-type":"SetSceneItemProperties","message-id":"69,OVERLAY_LOGO,False","scene-name":"OVERLAY_DESIGNER","item":"OVERLAY_LOGO","visible":false}