A few years ago I attended a lecture given by Messner's climbing partner Peter Habeler at the Royal Geographical Society here in London.
It was awe inspiring to hear how he and Messner in 1974 set out one afternoon to climb the North face of the Eiger one afternoon...until this time it had been an expedition of around 3 days...they set out in normal clothes wil a handfull of nuts to keep him going in his pocket...a record 10 hours later they were finished!!
When he went on to talk of climbing Everest without oxygen...well!!!!
BTW...I believe Habeler wore a Submariner as well as an Oysterquartz.