Originally Posted by PK.
A true Shaker door is a reversed raised panel. Some of the door manufacturers sell flat panel doors and call them Shaker doors. But there is a difference. When I make them I sometimes backcut the panel so the door is centered in the frame. (Although this also isn't a true Shaker door) Without the backcut, a 3/4" panel will sit proud of the frame unless you sand down the raised panel.
If you're talking historically, PK, then nearly all panels had the back relived a bit where they entered the rail and stile dados. So yes, historically a shaker panel would be "raised" on the back. As would any other door panel (others raised on BOTH sides. However, I haven't seen any cabinet or furniture manufacturer who does that today, so I'm not sure the point applies to the situation.