So here is what happened.

I called 2 days before the flight was to leave and was told the flight was still oversold and there were still (at least) 9 spaces available for upgrades. So I decided not to confirm the upgrade and try my luck for an op-upgrade at check-in.

When we got to the airport, however, everything had changed. The flight was not oversold any longer. So we handed in our certs but there were no seats that could be confirmed. We got put on the upgrade list. I asked and learned there were now only 3 seats left up front. Don't know how that happened but of course it could have been anything: missed connections, changed routings, etc., etc. (For example: I did hear the guy a few spots ahead of us in line have his reward ticket standby clear.) So I spent a couple of pre-flight hours extremely annoyed with myself.

Eventually we did get the upgrades and were seated together in 1HK, so everything worked out.

The moral of the story (for me): I got greedy and got smacked around for it (but just a bit). From now on, if I want an upgrade and it's available, I will take it and consider myself lucky. If I am fortunate enough to get an op-upgrade that's great, but trying to angle for one ahead of time is just plain dumb.

Lesson learned.