Looking for the year of application for this horn. Notice it is a single pole (for the positive wire) ground is obtained by the mounting bracket. It appears the horn button must be the positive wire and when pressed completes the circuit to blow the horn. I know it is not a 1940-51as these horns had double poles for + & - and the horn button completed/supplied the ground when pressed. Other than the terminals, it is identical in size, shape and sound as the 1940-52 horns. Thank you for your assistance. Harold
