Hi Ralf,
many thanks for your photo. Even if it is a little bit unclear, it seems, that Habelers watch has a date magnifier. Therefore I would guess the watch on the photo is not an Explorer 1016.

What wonders me is, that Messners watch on your photo has a black dial, but on the photo above (from oysterqaurtz.net) he wears an Oysterquartz with a white (or silver) dial. Strange….

Regards
Matthias