I don't remember seeing this thread when it was first posted, cool. The west coast certainly has it's fair share of interesting sirens. I agree that the paint can siren is not an HOR. I only know of like three different HOR models (though each one has several variations), and none of them are anything like that.
I'm sure you can easily hear a Model A in a car from far away. It's not much different from a firetruck siren, which you can definitely hear from inside a car without a problem.