A0283, the "Trapdoor" is a leading edge flap. The dual "strakes" physically push it up out of the way of the reverser door. They might be intentional vortex generators (they surely produce some vortices), and that may even be their purpose...none of my documentation over the last 20 odd years has mentioned them...but they definitely lift the leading edge flap out of the way when the reverser is moving. The ones in the picture are of a freshly painted aircraft...on a plane that has been is service for a little while, the paint gets rubbed off the top of them.