Yes, I do take the Genesis Apocryphon to be part of the Bible. Maybe being found in a cave in sacred wrappings next to copies of Bible books like Isaiah, etc., is a clue.

What "the Bible" is, however, remains very unclear. There's a lot of scholarly suggestion that the gospels, for example, was a story that was originally performed. The gospels, especially Mark, seem to have cues to performance.

I have wondered if the Genesis Apocryphon was a performed text and so not often distributed as a written text.