Has an International Rugby game ever ended 25-23?
It has. 25-23 has been a International Rugby final 2 times in 2,783 games. The first was Australia beat Wales on June 16, 2012; the latest was Australia beat France on November 19, 2016.
That makes 25-23 the 347th most common final score out of 844 that have ever occurred in International Rugby. One point away, 26-23 has happened 4 times and 25-24 has happened 5 times.