I'll have to pull the carpet up one of these days and look. These stocks seats are not too bad in the seat cushion area but have always lacked in the lumbar support region IMO. If the plugs aren't there I imagine this wouldn't be too difficult to wire since wiring is hot all the time.
One could always argue I could buy one with power seats but I've had her since new and will only part with it when the engine seizes.