Has an NFL game ever ended 12-10?
It has. 12-10 has been a NFL final 21 times in 18,234 games. The first was Brooklyn Dodgers beat Detroit Lions on October 6, 1935; the latest was Chicago Bears beat Minnesota Vikings on November 27, 2023.
That makes 12-10 the 241st most common final score out of 1,095 that have ever occurred in NFL. One point away, 13-10 has happened 170 times and 12-11 has happened never.