Yes, North Korea sent 51 athletes to the 2012 Games. There was a controversy at the opening match for the women's football event, when the South Korean flag was raised by mistake instead of the North. The team walked off the pitch and the match was delayed for an hour. As this was the first day of the competition, it wasn't a good start to the Games, added to the problem that a large number of seats had still not been sold. However, the team went on to win the match 2-0 and there was a public apology by the organisers.
In the end the republic had its most successful Games as far as medals were concerned; 6 medals in total, 4 of which were gold. Their most successful sports were wrestling, weightlifting and judo; this was the first Olympics to which they did not send any gymnasts, or any team athletes apart from in football.