There is a 1933 Pinball machine called "Silver Horseshoe" by field Manufacturing, but I can only see a reference to it in the guide...no pics that I have found yet.
Interestingly enough, there is another 1933 pin made by ABT that is simply 'Horseshoe". I realize it's not the same pin, but being made in the same year and with the shape of the horse shoes being very close to each other, I would almost bet one is a knock off of the other.