Is it possible to rebuild a dropped index?
I agree that "correct answer" isn't correct.

You can't rebuild indexes that have been dropped, you would need to create them again, and it would make no sense to do the insert last after the indexes have been dropped and created anyway.

I presume the correct answer is in fact something like


Disable the non clustered indexes.
Do the Insert
Rebuild the non clustered indexes.


As this is a heap this could be implemented with


ALTER INDEX ALL ON OrdersHistory DISABLE
INSERT ...
ALTER INDEX ALL ON OrdersHistory REBUILD


Which has zero impact on existing permissions, and low administrative effort compared with other possible alternatives such as the solution you propose of dropping and recreating all indexes.