A team has finished a game with 12-0 runs on that many hits 27 times since 1897, most recently Baltimore Elite Giants on 4 September 1949. That is about one every 16,407 team-games.
Box score for the most recent one ↗
10-4 11-0 11-1 11-2 11-3 11-4 12-0 12-1 12-2 12-3 12-4 13-0 13-1