Update:
Sorry, I see that "room" is the term used for "meeting" when entering the webinar itself. That's three different terms to describe the same entity. I'm sure there's a reason for this.
Anyhow, I created a new webinar under a newly-created account with minimal rights, made a recording and then called sco-contents. This time, it returned the expected result. What bothers me is that there is a recording out there associated with a known meeting sco-id that I cannot get information on. Could this be a bug?
Yours,
Mark