Yeah, all animations are 30hz, but all of then are interpolated to the current fps (60, 56, 432, whatever)… except vehicles animation that are not interpolated.
If you was in interpolated state inside a vehicle that is not interpolated, you will not be in sync with the vehicle, you will see the vehicle cockpit shaking, player butt will “dance” in vehicle chair. So player need to be with interpolation off when inside vehicle.
You will go into game code just to get the answers? This is ok for a straight* person you are, but… a little sad you have the time to do it.
*Edit: sorry, the word was “straight”, not “concise”.