I don't think your picture is of the drain plug, but the other plug on the right side of the engine (left side in these pics) beside the filter cover. In the following pics the top of pic is the front of engine. Drain plug is the 17 mm headed "bolt" on the left side of the motor (right side in pics) behind filter cover. Not sure what the allen headed plug is, but would guess it's an oil galley plug.
DSCF0007.jpg
and a closeup
DSCF0008.jpg
PS: click on the pics to see them full sized