Thanks for the link,sj. Last time I followed up on this was a couple years ago.
I picked up a 737 about 30 years ago and flew it all afternoon into the evening. The next morning I got the same plane and on first flight of day checks had no oxygen flow. Found the oxygen bottle replaced the day before before we got it had not been turned on so we were reading trapped pressure in the line.
Interesting about their mike selectors being in mask position and they passed out. That is probably what would have happened in our case.