Apparently DC's official stance is that he is not a master of all 127 styles since nowhere is it published stating it to be so. Glad we cleared that up. Myth busted until further notice.
Very well then here are direct quotes to support my claim:
"For he is a master of all fighting arts, his superb skill matched only by his courage!" - Det #411
"The Batman is superbly trained, skilled in every form of unarmed combat in other words, the perfect opponent, the perfect test! If our subject can defeat him we will know absolutely that our experiment is a success!" - Det 480
"However, the men do not need the Batman's warning nor is he merely a trained expert! Rather, he is the ULTIMATE martial artist." - Det 490
"As a youth I swore eternal vengeance of all criminals. To prepare myself for that war, I journeyed abroad to learn all I could from the World's Greatest Masters." - Batman #431
"He had picked up all he could from Grant (Wildcat) and moved on to his next teacher, and his next, and his next. With each new master he perfected a new fighting skill. He was becoming the sum of all his teachers and more..." - Batman Wildcat #2
"Ah. He exists. He appears. The Batman. The living legend. The man said to be the most skilled, the most determined, the most artful fighter in the world." - Lady Shiva (Detective Comics Annual #1)
Here we see Dick Grayson as Robin in the Teen Titans with Marv Wolfman pointing out how Batman trained in him in all styles of combat:
Of course I could list other quotes that seem to go against these claims as well which is why I said it depends on what the current writer goes by. But overall if you look at Batman's official origin or bio from DC they'll no doubt say he's a master of 127 styles of combat.