What Original Source Did David Barton Use for His Louis L'Amour Story?

Remember this?
Barton said he got his story about elementary school kids threatening an intruder in a one-room Old West school from a novel by Louis L’Amour. L’Amour was an Americana fiction writer who in 1986 provided Barton with some historical material he used in 2013.
I thought of Barton’s use of that third hand source yesterday when his son Tim told Gateway Church representative Kerry Wood that Wallbuilders only uses original sources for their materials. Barton said professors just have ideas, not sources. Back in 2013, Barton told Glenn Beck that in the 1850s, elementary school kids took guns to school and once saved a teacher from a would be attacker. Since the kiddies had their guns at school, they deterred the attacker from shooting their teacher.
Barton’s source for this story turned out to be a Louis L’Amour fictional novel Bendigo Shafter. Barton later admitted this but said it was fine because L’Amour said the story was true. Barton transcribed an audiotaped 1986 interview with L’Amour as follows:

There’s a case I [L’Amour] use in one of my stories; I use it in the story called Bendigo Shafter. All the kids coming to school used to hang their guns up in the cloakroom because they were miles from home sometimes, and it was dangerous to ride out without a gun. And this is taken from an actually true incident. I use it in my story and tell the story, but it really happened. Now a man came to kill the teacher. It was a man. And he came with a gun, and all the kids liked the teacher, so they came out and ranged around him with their guns. That stopped it. But kids twelve and thirteen used to carry guns to school regularly.

In 1986, L’Amour said the story was true but he didn’t point to any original source as Barton’s son insists is necessary. Without knowledge of the source of the story, Barton changed the details around (e.g., elementary kids instead of those aged 12-13 years) and presented it to Beck and the world as a historical fact.
First, watch Tim Barton tell his guests that the Bartons always use the original sources and then listen to Barton’s yarn to Glenn Beck about the gun-totin’ kiddies.

Maybe it did happen, maybe it didn’t. However, when Barton is telling the story, it is apparently fine to go third hand. When Barton is selling the story, the pitch includes all of those original documents.
This original source pitch is silly. Does Barton have the original copy of the Bible? The Constitution? We all have access to the primary sources for our governing documents. He may have some original documents, but if they are historically significant, they are archived for review by scholars. Good scholars use primary documents. Barton’s assertions here are fact free.
Barton is no stranger to second and third hand sourcing. For instance, his claim about Thomas Jefferson giving his edited version of the Gospels to Indian missionaries is third hand; there is no original source for that one.
See the following links for stories where Barton does not rely on primary/original sources.
David Barton Praises Primary Sources and Then Cites a Third Hand Jefferson Quote
Debunking One of David Barton’s Oldest Stories: Thomas Jefferson and the DC Schools
David Barton Claims Historians Don’t Use Original Sources and That is Why They Attack His Work (James O’Kelly story)
David Barton Uses Jefferson Quote He Says is Unconfirmed (see also this post on the Webster quote)