Came across this little snippet from The Washington Post, May 1999 with reference to what may be the same type of plate..........
"This Week's Contest was proposed, as it is proposed every year, by Mike "Mikey the Tout" Hammer of Herndon, who appears to have only one interest in life, and it is not Schopenhauer. We hear from Mike only once a year, around Kentucky Derby time, when he supplies us with the names of all the horses qualifying for the Triple Crown races and suggests we mate any two and come up with appropriate names for their foals. Maximum 18 letters and spaces. As always, you may ignore the genders of the horses, if – like Mike – you happen to know them. The full list of horses appears elsewhere on this page.
First-prize winner gets another fine pewter plate from the Baltimore mayoral administration of William Donald Schaefer."
http://www.washingtonpost.com/wp-srv/style/invitational/invit990502.htm