Yes, Moonroof it is, eventhough we call it glass sunroof in europe...
I know that in the newer cars you can replace the steel one with glass and the sliding cover and maybe you have to make some other mods as well, and I have a feeling I have seen a E420 (124) with moonroof, but I am not sure and I don´t know if the sedan and the coupé has the same measurements. So the question remains if someone should know.
Regards
L.