Box and device show a different serial number from the setting after my phone connected.

The serial number on the box and the product both come back saying there’s coverage available for another year. But!!! The serial number I can find through settings is different and says the Apple coverage is expired. ”Shouldn’t the serial number in the settings match the serial number on the box and the product???”

What does this mean?? are they really good fakes?? Please help with this question, thank you.