Gear Pre - 50:
Any Disciple of War gear /should/ have STRENGTH and DEXTERITY on them already.
As soon you hit 50, all monk gear (Allagan, i90, High Allagan) will be shared with Monk and Ninja.
However, when 2.4 is live, Ninja has their own gear set. They won't be shared with Monk, if i recall, (such as the Ironwork armor gear.)