7:07 on here, the whole forearm detaches just below the elbow
https://www.youtube.com/watch?v=9wDGcVjGFr4
Bicep straps/armour appear to move, however the shoulder armour appears to be magnetic so may be a few issues using the pre bent arm piece from the IW version?...
Thanks for the update. Looks like the guy in the video had a hell of time replacing that forearm.