Can you tell if she saw them after they were printed? If they were sent directly to you from the store, she may not have seen them and it could be the printer's fault. If you tell her, she can address the issue with the printer and maybe get correct ones. Plus, if the printer does not offer to correct the situation, she will know not to use them again.
If she gave them directly to you, the misspelling was probably her fault. But don't tell her as she may feel the need to buy you something again. If she at some point realizes her mistake, you can laugh it off saying that the misspelling is why you particularly love them because it means she knows you family's sense of humour.