The item you were given sounds like it is someone’s idea for lampooning stories that sometimes appear in the media that the Blessed Virgin has been spotted making an appearance in oil slicks, grilled-cheese sandwiches, tamales, and other ephemera. Because such “appearances” are not true manifestations of the Blessed Virgin, it is not sacrilegious to spoof them.
The principle to keep in mind is that when the Virgin or Christ or saints appear to a person, they appear. They do not “appear” as an image on something. Even the tilma of St. Juan Diego that was impressed with an image of the Blessed Virgin is not an “appearance” of Mary but only a miraculous image given as a sign to confirm Our Lady of Guadalupe’s actual appearances to Juan Diego on Tepeyac hill and to confirm her request for a church to be built on the site of her appearance.
As for whether it was appropriate to give a Catholic such a gift, it depends on the Catholic in question. If the Catholic’s faith would be shaken or if he would be scandalized, then the gift should not be given. Only if someone knows for certain that the Catholic understands the non-sacrilegious spoofery of so-called “food appearances” by Catholic saints might such a gift be okay – although not necessarily in the best of taste. Given the state of Catholic catechesis these days, it would be rare indeed that assumptions of Catholic understanding could be made. So, while a Catholic who does “get it” might purchase the item for himself for some innocent purpose, I cannot recommend giving it as a gift.
There is no need though to throw away this stamp. However silly the marketing of the item, the image sounds as though it is respectful enough that you could use the stamp to decorate Christmas cookies or desserts on Marian feast days.
Our Lady of the Underpass by Michelle Arnold
Our Lady of the Underpass, Redux by Michelle Arnold
Papal Pancake by Michelle Arnold