All item animation files are already public.
…\Steam\steamapps\common\Unturned\Bundles\Sources\Complete_Packages
So… ya’know. 
Also you should update your Unity imo. Any version of Unity 5.5.x will work, but the current version Unturned uses (until it upgrades to Unity 2017.4.3f1) is Unity 5.5.3f1. Just a little nitpick since the thread’s purpose is already kinda dead.