ok let me give it a shot
the hinge relies on a couple things . namely the constant pressure against the teflon slider. The handlebar folding is essentially the same on all models. It has been improved over the last years, as it is much stiffer on newer models

No problem I know of to turn it around.
The two hinges are adustable and can withstand a lot of static load ( they dont hold the full weight ofg the handlebar, but pressure them onto a flat surface ...

notch would have a lot of wear and tear, and would become sloppy

hope that helps

thor