Missing screws for plastic thigh

Hello,

In the box I received, there were pieces to assemble 2 wooden thighs, but also 2 plastic thighs (I don't know the reason actually ?).

The screw holes are bigger in the plastic pieces, so none of the screws I have allow to attach them.

Am I wrong ? Do someone know where to find the proper screws ? What are the exact screw dimensions required ?

Thanks !