Most new, branded items have unique identifiers that help buyers recognize and find them, including the item’s brand, manufacturer part number (MPN), and global trade item number (GTIN).
These GTINs can include an item’s Universal Product Code (UPC), European Article Number (EAN), or International Standard Book Number (ISBN).
You can check GTIN numbers here https://www.gs1.org/services/verified-by-gs1
Please check the latest information from eBay on the subject http://sellercentre.ebay.com.au/product-identifier-landing