I used to work at autometer through college, making tachs, oil and fuel pressure gauges. The gauge bodies (four years ago) used to be solid plastic and all the internal were put in through the front. The only hole in the back was for wires. The front bezel is probably a thin metal bezel that is press fit. If so you have to be really careful taking it off because they damage really easy. If it is a solid plastic case you will have to bend the backside of the bezel enough for it to slip off the front. The gauges might have changed since then, but if not like I said be careful because it will look really bad if you damage the bezel. When I worked there I took a face home and put Dodge R/T on it in blue (white face gauge) and assembled the air/fuel ratio gauge. It did look pretty sweet in the car.