3 section staff is monk usable, if the monk takes an exotic weapon proficiency Feat, just like every other class. The cestus, as listed in Sword and Fist has no damage listing like an armored gauntlet does, but seems to be a bit more like a piece of armor, but it doesn't have an innate AC bonus like a piece of armor. It states that it is made of leather with some metal over the knuckles. This makes it different enough from an armored gauntlet to cause me to ask the question. I am more inclined to say that if the rules don't expressly forbid it, it can be monk usable. I was just being sure that there wasn't a rule against it. If there is, then so be it.
Hawkeye
edit Forgot a word