A similar thing happened to me at LAX when I was flying LAX-IAD a few weeks back. The screens were showing 2 open seats in F, and I was #1 on the upgrade list. I didn't want to bother the GA, and figured she would start calling upgrades at some point during the boarding process. Well, by the time it was down to group 3, I figured I was pressing my luck on getting overhead space if for some reason I didn't get the upgrade. (The flight was oversold, and the GA made repeated announcements asking for volunteers willing to DBCFREE). So I went to the ticket counter adjacent to the gate and asked the agent there if they were clearing upgrades, and got a puzzled look and a "Yes" in response. A few keystrokes later, my NF boarding pass was in hand, and the counter agent was paging the person who was #2 on the list. I felt bad for bothering the agent, but I figured that the 15 minutes of boarding through which I had waited was more than enough time to clear upgrades (which is usually done before boarding even begins, IME).