The 95 S model I just parted out had two O2 sensors. The opening for the O2 sensor under the seat was located slightly behind the driver's seat front left mounting bolt. If you slide the seat to its rear most position you might be able to feel the wiring where it passes thru into the car.
While I did not try this personally because I was parting out the car, I believe you could access the connector for the under the seat O2 sensor without having to remove the floor carpeting. Remove the driver's seat (four bolts) and then the center console. With that done I believe you could reach the connector thru the opening in the carpeting that the transmission shifter and the parking brake poke thru.