All Teslas listed in existing inventory and on any used car site use the model year in the title. Tesla makes changes throughout the year so the model year doesn't mean much to a knowledgeable buyer but may be of significance to a less knowledgeable buyer.
Ultrasonic sensors are used for parking. Not for autopilot or emergency breaking. So tailgaiting has nothing to do with it. Tesla lists the four features they've had to disable in the cars without USS so those are the features that make use of them. Only one of those features (Park Assist) is on non-EAP/FSD cars. But it is a valuable feature IMO.
I agree that most buyers will have no clue. However, I was just browsing used Tesla ads and the most some recent ones had "ultrasonic sensors included" in the title even. But just like radar, Tesla may eventually just disable the feature on existing cars with the hardware anyways. If the speculation is true and the new 2023 cars have some updated cameras and Tesla disables USS on older cars then things might flip and a 2023 will become more valuable.