I bought a ‘new’ MacBook Pro from 3rd party. It came in a refurbished box, but they insist it was ‘new’ How do I know if this really is new or used?

When I received the MacBook, it was in a 2016 refurbished apple MacBook Pro box. (Even though the MacBook I received is a 2017 version). Are there any options that I have, to confirm whether this is a new or refurbished Mac. I saw online that I can ask apple to check the serial number and see if its ever been registered with someone else other than me. Will that work? Can I go to the apple store and ask them to verify it for me? Other than that, I received the MacBook exactly as I bought it, exact specs. I just thought that maybe they took the MacBook out of the original boxing and put it in a older box, but why would they do that, and why would they use an older box? Please help me out. Thanks, all answers appreciated. Just for reference, I bought this from Other World Computing.