If Apple sold you a refurb as new, then they've broken all sorts of laws, local, state, and federal. So, the chances of them doing that are slim to none. No, actually, I take that back. The chances are actually none.
Think about what would have to happen. First, your returned unit would need to be sent somewhere specific to be placed in new packaging along with accessories that would have to be placed in new packaging. Then the box would have to be sent to wherever the new inventory is being warehoused, and slipstreamed into the new inventory which was sent in lots from the factory. The serial number would have to be reset in their system, assuming you logged into your Apple ID with the unit (which was probably already linked since you bought it online, not sure how that works).
All of this would have to be done on purpose. There's no way it could happen accidentally. And so, Apple would be purposefully breaking the law, and to what purpose? Making a few extra dollars rather than just selling as a refurb?