My ATT specifically states that I need to be in possession of the registration certificate. A transfer notification is not a registration certificate. Therefore, no reg cert =no leaving the house with it.
Don't trust what some phone operator told you, they're not the ones in trouble if they give you bad advise and you get charged. Read the law, read your ATT, and then decide what is legal or not. Unless you got it in writing from them, their opinion is worth what you paid for it.
I've called twice in the same day with the same question and got two different answers. They don't know gun laws, they know how to answer phones and file paperwork.