There is very little doubt in my mind that the MotoZen levers fit the Thunderbird 1600. I know that cappy's dealership said no, but I see no signs of these levers even being attempted to be installed. It would not be the first time a dealership told a customer that something bought "elsewhere" would not work.
I blew-off going to my dealer today so I could get a joy ride in (hey, it's been 5 months since the last one). If I can only find a local (Oakland Co. Michigan) TB1600 owner that would allow me to try the levers on, I'd cheerfully would compensate them for their time.
I'll come to you.
"With integrity, nothing else matters. Without integrity, nothing else matters."