You can check that you have genuine Clay-Mates because real Clay-Mates all have a 'Hallmark' on their underside. This will tell you roughly which year your Clay-Mate was made..

• Before 2003 - No Hallmark used
• Between 2003 to mid-2005 - Hallmark - (Rolo's face)
• Between mid-2005 - Summer 2007- Hallmark -(Letters CM)
• Between Summer 2007 - Present Day-Hallmark-(Letters KK)