dual or single horn on 2008 Ford Fusion

i have a 2008 ford fusion awd / model SE. since buying the car new, it had a dual tone horn when touching the horn button. recently it only has a single tone. when my wife took the car to our local ford dealership [where we purchased the car] she was told that that car only has a single tone horn, and that it was fine. how can I verify that it should only have a single tone, or double tone?

Asked by for the 2008 Ford Fusion
I think the easiest way is to call the dealer parts department and have them look it up. they will ask you which horn if there are 2.