Except for locally-made versions in England, France, and Germany and perhaps elsewhere in Europe, all North American '32 Ford horns were either the initial motor-driven, so called boat tail horn because of the tapered cover on the back of the horn or the later vibrator type with a semi-circular rear cover. The horn in your photo obviously does not have a tapered cover and given that it is likely a motor-driven horn (ahooga), it was likely used on something built before 1933. The mounting bracket is unlike anything used by Ford on any of its vehicles before or after 1932 as is the trumpet given its length.
The tag might be informative if legible, but Ford wasn't the only customer of that supplier so it could be for any number of non-Ford vehicles.
IF it were a "German 32 Ford" it would have come, IF not with the appropriate Sparton BF or CF horn,, then the alternative would have been either a "HELLA" or a "Bosch Fk6AS4" horn. I am not sure about the British commonwealth. Here is the Hella and Bosch 32 Horns, the last 3 pictures of the Bosch FK6 AS4 horn!!!
