In 2010, the actual "Mookie Ball" was on display in the Mets Museum and Hall of Fame at Citi Field.
(Photo taken October 3, 2010. © Gary Dunaier. Link to upload on Flickr.com: here.)
(Photo taken April 19, 2010. © Gary Dunaier. Link to upload on Flickr.com: here.)
In 2011, the "Mookie Ball" was replaced by another 1986 World Series ball that was used in Game 6, signed on either side by both Mookie Wilson and Bill Buckner (signatures not visible in this photo).
(Photo taken May 18, 2011. © Gary Dunaier. Link to upload on Flickr.com: here.)