No.
Damaged leafs are still fully functioning energy drawing leafs unless they're hanging down. And dead they're still doing their job.
Any defol during a key growth stage. Is a no no. As Pre flower is a growth stage. Id leaf tuck if you want to allow the lowest leafs to catch some rays. As in pre flower that's all your plant does with the light it uses the leaves to grow your plant. Until calyxs have formed (bud) your leafs are your rains and can't be handed over to your bud (until the stretch is over, and calyxs have formed)