>>9920941still think it's a hobby base ball joint ... pretty much the exact ball joints a poly uses and the style he seems to have in all of their GKs as well
if some one wants to step in and correct me feel free
https://www.amazon.com/gp/product/B00MMWA23Ythis set will replace any joint in a poly except the wrists so I am thinking this set will probably be what you need for that GK