lol, of course they have glow plugs. And they have an inidcator on the instrument cluster. A line with two loops in it. On the tachometer, right side of center. It should briefly light when you turn the key to on. It won't stay on very long in most cases.
The light does not indicate when the glow plugs are on or off. It just indicates when the ECM says it is warm enough to start. Whent it is off, the car is ready to start.
It will flash when an non-emission fault is detected (has nothing to do with the glow plugs). If one or more glow plugs are not working the check engine light will be on (one of many causes for that light to be on).