A:AnswerWhat do you mean when you say open box?
This question is specifically asking about an open box product, which only Best Buy is going to be able to answer.
A:AnswerThis cellular version of iPad uses an eSIM, they no longer have a physical SIM slot. This appears to be the first version of iPad to use the eSIM. Version 9 and 10 still had a physical slot. I have mine tied to Mint Mobile who actually uses the T-Mobile network. Had no problem getting the eSIM information from them and entered it into the settings of the iPad.