Does every person who gets saved need the Holy Spirit to open their understanding?
Yes. Every person who comes to a saving knowledge of the Gospel must have their understanding opened by the Holy Spirit. He is omnipresent and available to all, never missing anyone, so no one can claim the Spirit never approached them. The true light enlightens every person.
Les explains that before the Jewish lady in Philippi could comprehend what Paul spoke, the Lord had to open her heart in the person of the Holy Spirit, and that has never changed. Every person who comes to a saving knowledge of the Gospel must have their understanding opened by a work of the Holy Spirit. The Holy Spirit is omnipresent and does not miss a soul, so no one can say He never approached them. Les also points to John 1:9, where the true light lighteth every man that cometh into the world, and Romans 1, where no one before the Great White Throne can say, "I never had a chance."