Thanks @
juvela 😁
The shifter boss is threaded, just not with M5x0.8. I suspect M5X1.0. Does the one-sided clamp you are referring to go over the braze-on? Or is it above or below it. The paint around the braze-on seem to indicate it goes over it.
I left facebook a while ago but I'll think about joining the group to see of there are any Bazou experts there.