FWIW MrWeezer & I flew ATL-DCA last flight out Christmas Eve last year. We were in first and it was mostly empty, flight load was light overall. So perhaps you will swing a holiday upgrade for you both (via companion upgrade). But in our case it wasn't really to our benefit in service, captain turned on the seatbelt sign & never turned it off & despite a smooth flight, FAs stayed seated. We suspect he told them ahead of time - I realize you're away from home on the holiday so Merry Christmas, it will be an easy flight for you.
If they're selling upgrades @ the gate you should be able to get the companion upgrade for no charge, correct? Ask the GA to confirm if it doesn't go thru in advance. Good luck & do report back!