This post is in response to a rush request from Jordan. I apologize for the lack of actual promptness, but here is the explanation behind the “Nag Hammadi” mention in S4E13.
In S4E13, the Gilmores are at a benefit dinner, and the speaker says, “That is why I thank each and every one of you for your loyal support to the Ephram Wordus Rare Manuscript Acquisition Foundation, because without it, we would just be stuck rooting around Nag Hammadi.”
One lovely thing about this reference is that it is briefly explained in the episode title itself: “Nag Hammadi is Where They Found the Gnostic Gospels.”
Nag Hammadi is a city in Egypt where the Gnostic Gospels were discovered (in a jar) in 1945. The Gnostic Gospels are a collection of thirteen books including the Gospel of Thomas and the Gospel of Philip. These books are based in Jewish and Christian tradition but for various reasons were rejected from the Canon of Scripture (they were deemed either untrue or unnecessary). The discovery of these manuscripts strongly influenced Christian scholarship in the twentieth century.
The speaker is basically saying that without a foundation dedicated to finding rare manuscripts, they would just be stuck looking in the last place they made a great discovery: Nag Hammadi.