The monsoon was available back then. It was either Stock Delco stuff or Bose. And if you didnt have the Bose setup, then you dont have an amp other than for the tiny amp in the HU itself, which is nothing to speak of other than to power the unit and get enough current to the speakers. Nothing more.
The only way you can truly tell if you have a Bose system is to look in the trunk and see if you have one these attached to the bottom of the rear decklid.
If that is not there? Then you do not have an amp in your GP.
I hope that helps to clear things up for ya?