[Supras] Alarm systems

[Bill]

Since it was a nice day outside (40 degrees) I decided to begin installing my audio own overheat warning system (like boats have; no more warped heads on MY watch!) and remove the after market theft alarm system. The latter has been the source of much aggravation, since we never had a key fob and had to rely solely on the valet switch to disarm it, every single time. I intend to put the wiring in the car back to its original state. My question is, did this car ever have a stock factory theft alarm? If so, how is it activated/deactivated? The stock horn will sometimes honk as an alarm, although the after market siren has long since had the wires cut. Should I be looking for an after market output to the horn, or is there something else I'm missing?

Thanks,
Bill 90 N/A