Keith,
The water rudder handle is an immediate giveaway. In case it's not clear, the water rudders are raised by pulling on the handle attached to a chain and the handle is then hooked onto the bracket on the panel. To lower the rudders, which are spring-loaded, you unhook the handle and put it on the cockpit floor. Low-tech but effective.
Instructors are not impressed if you try to take off or land with the water rudders lowered. They are only designed for use when taxying.
Another clue is the large "boat keyfob", which allows the keys to float when you drop them in the water!