Any idea for a replacement piece / technique | ball joint

Gomjaba

My set requires the Following two

2x2 Special Brick with ball (57909) and
2x2 Special Brick with ball receptacle (92013)

This is used for a wing that can be rotated accordingly. 

Problem is - I need those in Light Bluish Gray, and they don't seem to exist, or are really really rare. 

Anyone an idea what other parts that could be used to mount a wing (ideally within the 2x2 size) that would accomplish similar / the same type of rotation?