yes, surgical steel is usually something that is mentioned immediately by supplies sellers because it's almost as good as sterling silver as far as allergies, cleanliness and aging are concerned, so if your earring supplies said nothing about surgical steel, then they probably aren't.
The safest thing I'd think would be to consider sterling silver. It may be a little more expensive, but if you can remake the earrings or transfer the subject onto a new post or hook then it should be okay, but she may have to pay a little more to cover that. But that should keep them from irritating her ears, and if she wants them that much she might well be happy to pay an extra $5. Otherwise, if they can't be adjusted, altered or remade, just simply tell her that they are nickel free.