Incas is a weird name. I can't see it other as the plural of Inca, as in that historic people of South America. If such a name is used for a product, it's alway

Incas is a weird name. I can't see it other as the plural of Inca, as in that historic people of South America. If such a name is used for a product, it's always singular if the product is singular: e.g. Jeep Cherokee, not Cherokees. A box of chocolates shaped like aboriginal characters could plausibly be Cherokees (issues of offensiveness aside).