Marking it anything other than Species name and how many are in box is illegal.
marking it live harmless reptile or perishable is a felony.
Can be small hand writing on shipping label or stamped on the box and or use stickers. Though MANY do not do this since most are not aware of the law.
Me personally working with snakes day in day out(day job) ive yet to see a box go out and or come in marked whats in the box.