This photo could have only been taken in 1987 -- the only year in which Keith Hernandez would have had a "C" patch on his jersey (if you're really into uniform minutia, the "Rawlings" embroidery on the sleeve didn't appear until 1987 either). Did the Mets do the Opening Day II event in '87 as well as '85 and '86???
"The Mets made the best of their second home games in 1985 and 1986. They had Rodney Dangerfield throw out the first ball. It was only perfect for a game that routinely goes unrecognized and un-respected..." Article Here.
if you watch in the 1986 World Series DVD collection, during the special feature of the 1987 Opening Day ring ceremony, I remember a reference to "Opening Day II" being made. I'm too young to actually remember that game itself, but I remember Steve Zabriskie (I think) mentioning the term and it just sounded a little different. in another part of uniform minutia, i don't see the 25th anniversary patch on the jersey, so it couldn't have been 1986.