This too showed up at Hofstra and on Remembering Shea’s Flickr set.
From what I can tell, the original Mr. Met was downsized by the Mets in the late 70’s and replaced by Mettle the Mule.
Mister had two sons. The older (1.5) partied too much and didn’t take the job seriously, often looking wide-eyed and crazy in photos. The younger brother (Mr. Met II) went to school with Jeff Wilpon and is a more stable influence on children than this party animal seen on the 94 schedule.