Is there still an effective join phase for legacy raids?

Hi, we're thinking of running Sith raid next.

Once a legacy raid is autolaunched, is there still a 24 join period before scores can be submitted?

If a player solos the raid in 5 minutes as soon as submission begins, will the other players get the max guild crate at raid end even if they don't submit a score?

I read everywhere that the legacy raids last 2 days. How is that broken into join phase (if any) and score submission phase?

Thanks!