lamb shanks?

Yes... But shanks or leg, I would lower the temperature to 200 - 225 and go for seven or eight hours. It will produce incredibly tender meat.

Sure. It's basically a braise and a whole leg of lamb includes the shank. The timing may be different. I don't know that it will take 4 hours. Just watch them and remove them from the heat when they are tender. You can always reheat them later or even the next day. You also won't need as much liquid.