It’s a grain that very likely has traveled a long way through many situations and hands. Of course you wash it—even if the package says that it has been pre-washed. You don’t know what has happened since pre-washing, or that a bribe may have been paid somewhere along the line in a less regulated environment than your own in order to save in production costs. The Chinese, for instance, are notorious for that. Just check their honey products. It’s disgusting.
So, you don’t know. Use the method @Pied_Pfeffer above describes. Wash your rice, all your dried beans and any grain where it is practicable, as well. Kinwa has the added problem, like many stored grains, of growing live mold on it’s surface after it has been harvested—live mold that contain steroids These may be beneficial—which may explain the Incas’ reverence toward this grain—or damaging. You don’t know. You don’t know shit. So, of course you wash it.
Always ask yourself: WWABD? *(What Would Anthony Bourdain Do?)