No, the thor's hammer doesn't have a special drop shot button. Only the Odin's Raven has the two added tactile switches.
The Thor's Hammer does have a dropshot mode but it is NOT for the tactical layout, it is for just tapping the B button and your guy will drop all the way for you and you can immediately move your thumb from B to the thumbstick to start aiming, isntead of having to hold down the B button to make your guy drop...