Not talking about the arsenal sets rewarded by the achievements, but the regular weapons that drop when leveling.
There is a vendor that will sell you all the world content armor ensembles. But i could not find weapons. Weapons drop as personal loot for class\spec only while playing content. So, without a way to purchase them on the Bronze vendor, there will be no way to learn these mogs except to roll and level multiple characters that can learn them.
With everything else being available on the vendor and learnable by a single class (but only usable on the intended class) - it seems like a major oversight that the new weapon recolors are not also available this way.