Since the charging handle on a MAC-11 is a knob on the top, I don't think a top mounted accessory rail as shown would work unless there were either a cutout so you could reach the knob from the side, or if the charging handle were modified to have a lever sticking out through a slot or something.
After a Google image search, it looks like the accessories that match the rail in the picture are for airsoft guns, and they usually have a handle/lever sticking out the left side through a slot. The pictures I could find of rails that are made for the real weapon seem to have the rail mounted to the rear of the receiver, behind the charging handle, and often involve removing or replacing the folding wire stock.