Does every person have a chance to accept or reject God's salvation?
Yes. The Holy Spirit is omnipresent and works on every human being. Every person who has ever lived has been given opportunity to accept or reject God's salvation. No one can claim they never had a chance, just as no Israelite could claim hyssop was unavailable.
Les explains that hyssop was a common little bush or weed that grew everywhere in Goshen, similar to ragweed. Because it was everywhere, no Israelite could say he had no chance to find hyssop and apply the blood as instructed. Les likens hyssop to the work of the Holy Spirit. Since the Holy Spirit is omnipresent, He works on every human being, and Les is firmly convinced that every person who has ever lived has been given opportunity to accept or reject God's salvation. Just as hyssop was common and available, so the Holy Spirit's work means no one can say the Spirit never worked in his life.