In '93 to '95, the CA VX had a 4-wire O2 sensor. But in '92, the CA VX had a 5-wire sensor, just like Federal. But all CA VX ('92-'95) came with the CA ECU, which does not fully utilize the 5-wire sensor and hence does not support lean burn.
Does your dash cluster have an SIL (shift indicator light)? This would be a clue that you're Federal. But of course the cluster could have been swapped.
You can also check the sticker under the hood. On a CA car, it will say something like this: "this vehicle conforms with US EPA and state of California regulations." But this is also not definitive, since hoods can be swapped.
The other two signs of a CA car are the ECU and the O2 sensor. Also the engine wiring harness, which will correspond to the O2 sensor.
You have a California car if your ECU ends in l00. I have the same car. You can enable lean burn by simply swapping in a Federal ecu. This only works on 1992 cars. If you had a 93-95 Cal. car, you would have to convert the 4-wire to a 5-wire.