Has an NBA game ever ended 80-77?
It has. 80-77 has been a NBA final 20 times in 77,318 games. The first was Washington Capitols beat Philadelphia Warriors on March 11, 1947; the latest was Boston Celtics beat San Antonio Spurs on March 20, 2009.
That makes 80-77 the 985th most common final score out of 3,189 that have ever occurred in NBA. One point away, 81-77 has happened 12 times and 80-78 has happened 25 times. Nearly all of its occurrences fall between 1980 and 2009. At one point the score disappeared for 33 years, between 1952 and 1985.