Has a La Liga game ever ended 7-2?
Yes. La Liga has seen a final score of 7-2 25 times. It first happened on February 2, 1930, when Arenas de Getxo beat Real Union, and most recently on September 13, 2003, when Real Madrid beat Real Valladolid.
That makes 7-2 the 27th most common final score out of 51 that have ever occurred in La Liga. One point away, 8-2 has happened 13 times and 7-3 has happened 11 times.