It looks to me that the label was once on the stone and wrapped around the sides - the bits that were on the sides are missing. The box most likely did not come with the stone - it was made for it by someone - probably the same person who removed the label from the stone and stuck it on the box. I'd ask for a photo of the stone on top of the box so I could see the label against it to get an idea if the ragged edges correspond to the sides of the stone.

Regards,
Neil