If I understood correctly your question Not only you can add to a 2d panel a six gauge ,you can add a hundred ,you can Make another panel ,modified the color see, the 2d panel does not belong to the mdl model or root model, Open the panel and there is a Bmp file you can open it , and if you buy the FS Panel Studio for FSX you can modified or create and entire panel 2d
I think you mean the mini panel. The number & type of gauges will depend on the aircraft. Some have their own [MiniPanelxx] entry in Panel.cfg. Aircraft without these entries will use the default MiniPanel.cfg located in FSX\Gauges. I'm not sure if all gauges will work on the mini panel. If you're familiar with editing panel.cfg files you could experiment.