Not exactly. Spacer would push the camera further away from the roof and making it more exposed to rain and wind. Having it right against it roof, keeps it almost completely away from rain and wind. I know the unit is weather proof, but having rain on the lens would degrade picture quality. So I would prefer not to add spacer.
Based on the suggestion someone had, if the orientation info of the video is saved then the video play can better put it in the best viewing orientation. I would think that upside down and portrait orientation can be handled the same way. Just that the orientation would be either 90, 180, or 270 instead of 0 degree.