Quick glimpse of the basketball game Vinny is watching in bed is clearly not the 1990s.
Around 00:53:50, Vinny is holding a long pasta with his fork. On the next shot, all pastas are short.
Vinny Pazienza won the Duran fight by a wider margin than it is shown in the movie. Instead of a majority decision (114-114, 115-113 and 115-113) it was a unanimous decision (117-113, 117-112 and 117-112).
Late in the film, the TV in Vinnie's living room makes reference to the Red Sox "chasing the Yankees for the wild-card...". The concept of a "wild-card" wasn't introduced into MLB until 1994, over 2 years after the scene takes place. Neither Boston or New York were in contention as division leaders during the later part of the 1992 MLB season.
Vinny Pazienza didn't make his comeback against Duran. He had actually won 6 fights in 1,5 years after his return from injury before he fought Duran for the 1st time.
At the beginning of the Duran fight the commentators say that Pazienza is trying to win the belt 3 weight classes higher than the one where he had won his 1st world title. Actually, the gap was 5 weight classes (between lightweight and super middleweight).
There was no Twin River Casino at the time of these events. It did not open until 2007.