I believe some do not have the internals for a light, but not completely sure about that. Here is one I did a LED upgrade on for a friend. Since I have a 91, the switches are different, so I would check and see if your switches have 4 connectors or just two, or just pop them open like shown in the pic to find out. I have only dealt with the one I upgraded, so that is all the experience I have with that particular switch.
You must be registered for see images attach
All of the 95+ cargo light switches i have messed with had lights in them. Gotta remember these switches are atleast 13+ years old so the bulb is probably burnt out.