You're right if you are moving to FT bars, there is a little lever holding the electric plug into the speedo.
The speedo has to come off when changing to the bigger diameter clamps used for FT which doubles as the speedo mount.
If you just fit 22mm bars from something else then the clamps and speedo can stay.
The settings stay OK according to those who have changed so far.
Yeah you have to pop the speedo off, this doesn't effect any info on the speedo. Also worth noting to take the 3 little rubber spacers off the old clock mount and add to the new! I had a head scratching moment for 5 minutes as to why the speedo was rocking slightly!