If you are looking online (I'm assuming for CPO Teslas), use ev-cpo.com to search. They pull the vehicle codes from Tesla's online listings, and you can search by option to see whether a vehicle has what you are looking for.
If you are physically in the vehicle, click on the audio equalizer/adjuster icon - if you see a check box at the bottom that says "Dolby Surround" then it would have UHFS. You can toggle this on or off depending on your sound preferences.