How to get controller to show up on GearVR and Oculus Go with Unity build?

Hi, it looks like OVRInput.GetConnectedControllers() is returning zero on the GearVR and Go when built using Unity 5.4.2f2-GVR13.  The devices have matching website-generated oculussig_ files placed under Assets\Plugins\Android\assets\ .  Is there something special that must be done to the apk separately to enable controller support, etc.?