Question Can ARCamera have child objects?

I want to attach an object to the ARCamera, like a FPS gun that moves with the camera. I've attached an object but it doesn't render.
How do I fix this?

Thx

 

It is no problem to attach stuff to the camera. They will move as you would expect from any other parent/child relation.
What you might encounter is that the field of view is adjusted depending on the device you are using - thus the preview in the unity editor might not give the same result. I would try to place the object right in front of the camera to check if that is your problem (within the clipping box).