Yes, that is all that it is. Though, he does back up what he says with very good reasoning and his parallels between the new and old testament ring true and are very interesting.
Take for example his explanation of why the serpent is actually a dragon,
*"The Hebrew word used to describe the “serpent,” nahash, implies something much more deadly. *
*Throughout the Old Testament nahash is used to refer to powerful, even gigantic, evil creatures. Isaiah calls the nahash a sea dragon, the great Leviathan (see Isaiah 27:1). Job also uses nahash to depict terrible sea monsters (see Job 26:13). *
This is clearly the image the Book of Revelation has in mind when it describes “a huge red dragon” in the heavens, “the huge dragon, the ancient serpent, who is called the Devil and Satan, who deceived the whole world” (see Revelation 12:3,9)."
If you want to read a summary of the explanation from the book you can find it here at the Pope Paul Center for Biblical Theology.
salvationhistory.com/studies/lesson/genesis_creation_fall_and_promise#III.B.
Btw, I love how he speculates that Mary Magdalene in mistaking Jesus for a gardener is also a reference to Adam who was the keeper and protector of the garden.