It should be noted that there are a lot of "books" and "gospels" that didn't make the cut when the various versions of the Bible were assembled over the course of centuries.
The fact that one made it in, and another didn't is no proof of eithers validity or lack thereof.
Assuming that "authenticity" here, means historical accuracy, it should be noted (in both cases) that such accuracy is a dubious concept in documents written some two to three centuries after the events they describe.
