To be absolutely certain, you should:
* Consult a repair manual specific to your 1997 Buick LeSabre: These manuals have diagrams showing the exact location of all sensors.
* Use a reliable online parts diagram: Sites like AutoZone, Advance Auto Parts, or RockAuto allow you to select your year, make, and model and view diagrams of the engine.
Looking at these resources will give you the most accurate location, avoiding any guesswork. Remember to be cautious when working around the engine and disconnect the battery negative terminal before starting any work.