Luck scrolls have always been worth 2 Dooms. Double score would be 4 Dooms.
Edit: And yes, I’ve verified. I scouted/full cleared to floor 16 without ever removing the event weapon and each luck scroll was always 2 dooms. I’m sitting at the start of floor 17 with 38 doom (2 * 16 = 32 for bosses, 2 * 3 for luck scrolls)