Super Bowl XXI - Giants v. Denver Broncos
Giants favored by 9 1/2 - Final score: Giants 39, Broncos 20 Super Bowl XXV - Giants v. Buffalo Bills
Bills favored by 8 - Final score: Giants 20, Bills 19 Super Bowl XXXV - Giants v. Baltimore Ravens
Ravens favored by 3 - Final score: Ravens 34, Giants 7 Super Bowl XLII - Giants v. New England Patriots
Patriots favored by 12 - Final score: Giants 17, Patriots 14
Cowboys and Texans
According to Wikipedia, the Bills were an eight point favorite over the Giants in Super Bowl XXV.
The New York Giants were 9 point favorites over the Denver Broncos ... the Giants won 39-20.
Patriots +12 over the Giants.
The Patriots won all 3 of their Super Bowls against the Rams, Panthers and Eagles by a 3 point margin (the point value of a field goal), but only their wins against the Rams and Panthers had the field goal be the game winner.
The New York Giants defeated the Buffalo Bills in Super Bowl XXV. The score was 20 - 19.
No teams remain at this point with 4 Super Bowl wins. The Pittsburgh Steelers, Dallas Cowboys, and San Francisco 49ers have each won 5 Super Bowls. So in a sense they have each won 4 Super Bowls but no longer remain at that number.
Super Bowl XXV between the New York Giants and Buffalo Bills was decided by 1 point with the Giants winning 20-19.