I can't confirm whether this is the correct reflector for an E500E - others on this forum may be able to confirm or otherwise.
However, you are right that the "standard" W124 reflector differs from that for an E500E. This is because on an E500E, the right-hand reflector (as you are looking at the picture you have posted) is a spot/long-range/driving lamp, whereas on a "standard" W 124 this is the fog lamp. On an E500E, the fog lamps are situated each side of the lower front bumper air-dam.