Yes. He has a printed boarding pass from HNL, but I clarified with him, and that one had a coach seat assignment, because he was only upgraded on the LAX-DFW segment as he was about to board the HNL-LAX segment. He screenshotted the new J boarding pass in row 5 for LAX-DFW at that point, which is why he was trying to show the GA his phone at LAX, and she rudely told him she didn’t have to look at passengers’ phones.

It was this mobile boarding pass that resulted in the beep when it was scanned at the LAX gate.

Of course, even the original Y paper boarding pass is sufficient proof he was checked in, as complimentary upgrades do not result in reticketing and the need to check in again.