My truck is a tradesman. There's just one rear dome light, all the way at the back of the roof. It comes on when you open the doors or turn on "all lights" from the dimmer switch. You can't push it as it's just hard plastic.
They are all hard plastic, have you tried pushing on it?
And, they are all single lamps at the rear center of the cab.
If the tradesman doesn't have this type of lamp, then I guess you could get one from a higher trim level truck and install it.