When a new Mac is not able to be sold as new, (dues to complexities of the uniform commerce regulations) it is sent back through the manufacturing process, refreshed back to showroom condition and re-tested, and re-appears as "Apple refurbished".
Apple does not sell any "Open Box" goods, at all, ever.
You are dealing DIRECTLY with a seller, who at least is honest enough to report its condition, and not try to sell it to you as new. However, if they did not do EXACTLY the steps required to return it to "like new" condition, or it is actually stolen property, you will NOT be able to use it for anything except a doorstop. if you are dealing with an individual with the ability to disappear and NOT be held accountable, your money is also likely to disappear without a trace.