I am not surprised that the bodies are unique to the 1100. They are mounted on top of the engine in the 'V'. This is not a common location for them because there are relatively few V-4's powering mc's. While the other parts - needles, jets, floats, etc. can be used in other carbs, the float bowls make carbs position sensitive - you cannot flip them 90 degrees and have them work on another bike. Downdraft carbs were more common on big auto V engines where they could sit atop the engine just like our ST's. It would be more likely that a horizontal flow carb would find multiple applications (bikes). I do know that a few different carbs were swapped on old Guzzis, and way back when, we were talking about improved performance from different carbs on a number of bikes.