These dual jetways do work with several type of aircraft, at least at AMS. Their use is not limited to one type. At AMS typically KLM would be using gate X [equiped with over-the-wing jetway] in the morning push for 743 and 744 [both full pax and combis], the midday push could see the same gate being used for MD11 and the afternoon push could see an 767 at the very same gate. However, the 767 won't be using the over-the-wing jetway, only the front one. Take a good look at the second pic in the original post. The US Air 767 is parked at dual jetway gate, but the over-the-wing jetway is not connected, it is just hanging over the wing in its most elevated position. The front is connected though, as can be seen clearly.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"