Re: rage are re-airing the May 3, 1981 Countdown on ABC *now*
It happened this morning (Friday morning), ABC.
But they only played one Countdown. It was followed by a repeat of a Saturday morning segment (not the retro month hour).
rage doesn't normally air on Friday mornings on ABC, so I don't think there's a set 'theme' for the show when it does. When I've caught it before, they've aired new releases, or the top 20 chart if there was no episode on Thursday morning.