Authenticator Pre-Certified Authenticator: Upper Deck Authenticated History of item: Steve Kerr has signed this item in the presence of a representative from Upper Deck Authenticated. Describe how you came to possess this item: Game Day Legends is a fully authorized retailer for Upper Deck Authenticated. Other information about you and / or the item: Game Day Legends strives to deliver the most authentic in sports memorabilia from trusted companies like Upper Deck Authenticated; Panini Authenticated; Beckett Authenticated and Fanatics Authenticated.