You missed the beginning words.
This book is edited from the lectures and unpublished notes of R. B. Thieme, Jr.
The original messages almost always referenced the KJV.
I have yet to hear him give a lesson beginning with the NASB
Why they chose that route I can not tell you.
He almost always cited the KJV in the unedited original classes.
A devout student of his, my former pastor Rick Knapp, started with the KJV when he taught at Soldiers and Sailors Memorial.
I noticed gradually over the years as he studied greek, he gravitated towards using the new versions. Eventually he would undermine the King James traditional text for his own translations. Is that what Theime did too?