Are you sure that is the 1987 (away) game and not the 1988 (home) game?
Michael Irvin frequently did a "U" where he put his thumbs together and then held up his index fingers, as if he was making a goalpost for paper football.
When F$U would do their warchant (which was originally just for offensive possessions), Miami fans would respond to the tomahawk chop with either a one-handed or a two-handed chop with extended middle finger(s). This gesture frequently made it into the TV broadcasts.
Tad Foote and others were not happy. I believe that Bill Tigano (a former cheerleader) claims that he came up with the "U" hand symbol in 1992, and I think that his claim is that it's the "thumbs together plus all fingers upright" version. There is a Miami Hurricane article that credits a UM student back in 1984:
https://www.themiamihurricane.com/2014/11/12/fsu-game-inspired-first-man-to-throw-up-the-u/
Clearly, between 1984 and 1992, the "U" hand gesture began to grow and mutate.
There's a reason why I don't believe Bill Tigano's claim. I was an undergrad at Miami from 1986 to 1991 (graduated in 5 years after switching from Engineering to Business). One of my best friends was in the Band of the Hour. When we were playing in the Orange Bowl (86, 88, 90, 92, etc.), our band's response to the Warchant was to play the Imperial Death March from Star Wars. And Connie Nickel (the administrator who led the cheerleading teams) instructed all of the cheerleaders to have the student section do the "U" hand gesture during the playing of the Imperial Death March.
It was, literally, an attempt to get the student section to do something with their hands instead of extending their middle fingers for the Tomahawk Chop, particularly since UM had a partnership with the Seminole Indians (Iron Arrow, UM's Highest Honor Attainable) since the 1930s.
So Bill Tigano may have been photographed doing the "U" hand gesture in 1992, but I specifically remember the cheerleaders (particularly Val, who was more imposing than Bill) trying to convince the drunken student section to do the "U" while the Band played the Imperial Death March...BEFORE 1992.
And, sure, I was heavily inebriated for most of those games, but I'm fairly certain of my recall on this issue.