MEC free position buttplate and hook - hook wont go on

[Modena]

I have my new rifle, sorry will post about that later, but for now I am having trouble with the MEC free position buttplate, specifically the hook.

In the pic below where the red highlight is, my hook will not go on the rod end, the hole in the hook is just not big enough to take the knurled rod. what am I missing? Yes I have the screw loosened, there's no way the hole is big enough to take that knurled rod.....

I will try to get some pics of my actual buttplate tomorrow, its late now and maybe I'm just missing something obvious.....