Your sample code is undoing the negative x scale, which is required for inverting the hand and making it look left handed. Use the following code instead:
Code:
myHand = viz.add('hand.cfg',pos=(0.1,1.8,0.5),euler=(0,-90,0))
myHand.enable(viz.FLIP_POLYGON_ORDER)
myHand.setScale(-20,20,20)