Sila is a prerequisite for Samadhi
Samadhi is a prerequisite for Panna
One cannot have Samadhi without Sila
One cannot have true Panna without Samadhi
True Panna means true insight where one sees all formations as they really are and without false perception of permanence, pleasant and self in them.
One can however approach magga-phala by Samadhi first Panna later or Panna first Samadhi later.
Panna first Samadhi later uses panna as a base to cultivate Samadhi. This panna however is not true panna rather a perception based panna which in tandem with Samadhi develops into true panna which turns into fruition attainment.