Has an NBA game ever ended 87-78?
It has. 87-78 has been a NBA final 20 times in 73,172 games. The first was Philadelphia Warriors beat New York Knicks on December 17, 1948; the latest was Dallas Mavericks beat Oklahoma City Thunder on March 3, 2021.
That makes 87-78 the 985th most common final score out of 3,189 that have ever occurred in NBA. One point away, 88-78 has happened 27 times and 87-79 has happened 31 times. At one point the score disappeared for 27 years, between 1962 and 1989.