Your new images show that the spigot on the left side is definitely hexagonal.
That has to be important. It's easier to make it round or square. So it has to be hex for a reason.
Also there is a triangular strengthening web at the base of that end plate, and the metal around the spigot is thicker (end image), suggesting that the designers expected a lot of bending force on that plate.
That seems very odd.
Also, the metal base is asymmetric. There is a hole on the side nearest the camera, but the equivalent on the other side is solid.
Finally, the new images show a hole in the end of the bolt? o the left hand end. You can just about see that the hole penetrates through to the scoop in the bolt(?)
What seems odd to me is that it looks like a very complex assembly with unusual hinges and bearings ... and then there is that hex spigot.
Can't figure this one at all. Sorry.