Honestly I don't know with certainly. However, there's no reason to think that a single action by Adam or Eve made them lose their salvation. Genesis doesn't suggest that their salvation was tied to their obedience or The Garden of Eden.
It would seem like Adam and Eve eating off the tree would not cause them to not be able to correct that if they wanted,and be right again with God by repenting of it,for sin is sin.
God has commandments that are spiritual,moral laws,and laws of love,but if we violate we can be forgiven,so Adam and Eve could of been forgiven too.
Gen 3:11 And he said, Who told thee that thou wast naked? Hast thou eaten of the tree, whereof I commanded thee that thou shouldest not eat?
Gen 3:21 Unto Adam also and to his wife did the LORD God make coats of skins, and clothed them.
God clothed Adam and Eve with coats of skins from animals.Did God do the first sacrifice in the process,and cover Adam and Eve's sin?
I believe Adam and Eve could of been forgiven.But obedience is tied to salvation,which bring every thought in to captivity to the obedience of Christ,and to obey is better than sacrifice.