Plot hole: Marie says at the beginning that Chuck quit writing after Swan Song (season 5). Later she says she hates the "Metastories" which don't happen until season 9. She couldn't have known about the Metastories since those books were not published.
Continuity mistake: Both Sam and Dean show no signs of bodily damage or harm, even though in the previous episode "Shadow," both brothers were attacked and their faces had been slashed by the shadow demons summoned by Meg.
Character mistake: Sam describes the books as being from "pre-Biblical lore" and then says they are written in Aramaic. Aramaic was a language during New Testament Biblical times and didn't exist in pre-Biblical times i.e. prior to 4000 B.C.E.