Yes it is. As far as I know, they’ve never found the airliner.
I think there have been reports that bits of debris from the plane were found (maybe somewhere around Madagascar), but I am not sure if they can tell definitely they are from that plane.
True. But it's a certainty it didn't go down in Pakistan.
A piece of wreckage that washed up at Reunion Island was determined via serial number to be a flaperon from MH370.
Reunion Island is in the Indian Ocean, east of Madagascar and way west of the search area, southwest of Australia.