I was number two on the upgrade list Tuesday, ATL-LAS. There was one seat remaining in first. Boarding for Zone 1 had begun and I was then number one, guess the other passenger had boarded. After a bit I asked the gait agent if first class was full and she said one seat was available. When I said I was number one she said they had planned to finish boarding and then call for the upgrade which would be the former number one not me.

I guess the way these things are handled depends on the gate agent not a specified and enforced policy.