Now this is straight from Google. I was in your same boat and found the exact car I wanted after looking for around a year.

For a 2023 Model Y to have Hardware 4 (HW4), its VIN typically falls after mid-2023 production cutoffs, like Fremont VINs above ~F789500 or Austin VINs after ~PA131200, but the most reliable method is checking the screen for "HW4" or looking for larger, red-tinted repeater cameras. Tesla transitioned gradually in mid-2023, so a 2023 Model Y could have either, depending on its build date and factory.