Manufacturer: Syracuse China
User: New York Mets, Diamond Club Restaurant
Date of plate: October 1968 (the year before the Mets won the World Series)

 

Notes: Winthrop shape. The plate would have been used in the high-end buffet served by the Diamond Club Restaurant in Shea Stadium, located on Roosevelt Avenue in Flushing, Queens, NY.

From the club's website:
The Diamond Club Restaurant is located on the Press Level overlooking the field. This 300-seat, fine dining restaurant offers a spectacular full buffet.