I believe I have solved the mystery.
Today, I called Papa John's (1-888-404-7537) and spoke with Diane Helms (the PJ director of domestic R&D--same gal I have spoken to before), about the reference in the PJ Facebook video at
to a particular kind of seed used to make the PJ flour. As previously noted, the reference is at about 3:15 in the video. I asked Diane what John Schnatter was saying about that seed. She said it is the Platte River seed. She went on to explain that that seed was developed specifically for PJs in order to achieve a particular flavor in the finished crust. The flour itself is a proprietary flour that is milled specifically for PJs and whoever does the milling for PJs is not permitted to sell the flour to anyone else. It is exclusive to PJs. Diane believes that the name Platte River was given to the flour by people who were involved in coming up with the particular seed used to make the flour. It is not something that someone can go and ask for and expect to end up with the PJ flour. A quick Google search shows that there is apparently a Platte River in Nebraska.
I also asked Diane about the protein content of the PJ flour. I specifically mentioned that at one time PJs promoted their flour as being a "high-gluten" flour. She said that that was still true. When I said that to me "high gluten" meant around 14% protein, she said "Well, it isn't quite that high". As I have mentioned before, I have suspected that PJ's flour was in the 13.0-14% range. I think that that may also be true of many of the large pizza chains. For one thing, it tends to lend itself better to a delivery type pizza than a pure high-gluten flour.