I believe it does. When playing through the story, my brother happened to pass through that area on Thursday. He caught Mandibuzz and used it in his party. Weak Armor beyond sucks for Mandibuzz, but still.
Yep, Mandibuzz is Black 2 exclusive for every Thursday and always has it's hidden ability. The same goes for Braviary on White 2, except that it spawns every Monday. --- "Evil, beware. We have waffles..." - Raven, Teen Titans