Has an NBA game ever ended 85-80?
Yes. NBA has seen a final score of 85-80 20 times. It first happened on March 12, 1949, when New York Knicks beat Chicago Stags, and most recently on April 20, 2012, when Memphis Grizzlies beat Charlotte Bobcats.
That makes 85-80 the 985th most common final score out of 3,189 that have ever occurred in NBA. One point away, 86-80 has happened 26 times and 85-81 has happened 29 times. Nearly all of its occurrences fall between 1980 and 2009. At one point the score disappeared for 33 years, between 1955 and 1988.