Those alive before Adam and Eve had the internal knowledge of right and wrong [often did not listen to it though], they did not have the laws [Commandments of God], were able to see that God existed through the knowledge of animals, Earth, Sky, Heavens, Sun, Moon, plants, etc.; thus, they had the ability to choose to believe in God Almighty. They did not know of Jesus or the Holy Spirit and, thus, the Trinity. Humans are born with a conscious but often choose to ignore it.
If these 6th day humans believed in God and wanted to please him, they would have upon death gone to wait Judgement Day and been given the same choice to accept Jesus when he died/arose and moved Paradise to Heaven thus being also saved just as Abraham, etc. were. However, these humans probably did not make this choice as God then made Adam and Eve to guide all humans to live for God. Unfortunately, Adam and Eve fell into sin.
Bottom line: It is most likely the 6th day creation humans were not saved at any point. It seems that humans were mostly into idols of some kind instead.