You definitely don't want to let your boy get away with this behavior, otherwise he won't respect you as leader. I would suggest working on teaching him that when he has high value items that he doesn't need to fear you taking them away from him. Dogs will growl when they have things because they want to protect what they have. They protect what they have because they don't want it to be taken away.
Show your dog that you aren't there to take his stuff away, but you are there to enjoy his company. Do this by feeding him treats when he has high value items. Practice exchanging his bone for treats, other bones, toys, anything. Give him a treat, pick up the bone, then give him the bone back. Enough repetitions of this will erase your dog's desire to protect things from you.
Reinforce your leadership role by practicing obedience with your dog every day. NILIF - nothing in life is free. Make your dog work for you before petting him, letting him go for a walk, eating his meals, fetching his toy, etc. All this together should cause this behavior to disappear, and your relationship to blossom
