Two things make it difficult to give a definitive answer concerning the salvation of Adam and Eve. First, there is no direct statement of a salvation experience in the Bible. Second, we have no statement as to what exactly would compose salvation for them. However, having said that, I will say that I believe that they were saved. I have two arguments for this.
Adam and Eve were certainly used as a type of salvation. After their sin, they discovered their nakedness and then tried to cover it with fig leaves through their own efforts (Genesis 3:7). This, of course, failed miserably and their sins were exposed and judged. However, God in His mercy created another covering for them. He made them "coats of skins, and clothed them" (Genesis 3:21). The blood of these animals had to be shed so that their skins could be used to properly cover Adam and Eve. This is clearly a picture of salvation. And, although it is simply a type, I think it would be strange to give a clear type of salvation using people who were eternally lost. It would seem contradictory to do so. Therefore, I think they were saved.
- Despite their disobedience, it is to Adam and especially to Eve that the promise of the coming Redeemer was first made. In Genesis 3:15, the Lord said, "And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel." This is the first great prophecy of the coming Messiah. But not only that, it is obvious that Eve was looking for His coming. When Cain was born, Eve declared, "I have gotten a man from the LORD" (Genesis 4:1). Surely, this was more than general thanksgiving for a son. Eve thought Cain was the promised seed who would bruise the head of the serpent. People who have rejected God do not anticipate the coming of the Redeemer. This is the second strong evidence that Adam and Eve were saved.