So I also dont have this part, but after looking at OEM Ostro forks I also dont think its required.
Here is a photo of the OEM Ostro fork, you see how its flat? its requires that wedge to provide support around the perimeter

Here is a photo of the ALI Ostro fork, they have modified it, its almost like they incorporate the extended perimeter, thus not requiring the wedge

I guess we get to find out if its a good design or not
