In my experience once you are completely checked in (meaning you have had your visa verified at the airport if you are on a flight to Brazil or China, for example) then you wil appear on the upgraded list. Right after 3/3 I had a couple flights where I did not appear on the list, and I would say this was consistent with the comment about it depending on final booking class, but the last few times I was upgraded usng a GPU I have appeared on the list regardless of whether the upgrade was processed days in advance or at the gate and regardless of the fnal class showing on my boarding pass.