Just watched the video, lots of mistakes and omissions in it... Even if it's interesting.
The first Precision Bass had bakelite saddles, not carbon, that had a tendency to break.
The pickguard was in wood first painted in black (over a can), then bakelite, then plastic.
The first electric bass player was indeed the vibraphonist Lionel Hampton, but the first real electric bass player to record with it was Monk Montgomery in 1953. He played the Precision Bass because Lionel Hampton insisted on it when he joined back the band in 1952. He then only played an electric bass with his thumb, just line his brother Wes playing the guitar. He is also known to have been the best Fender bass ambassador over the early years.
The 1968 Fender tuners or machine heads are referred as Lollipop tuners.
The action on James Jamerson's funk machine was high because the truss rod was broken, not because he was a double bass player, but the fact he was one pmade it happen because this higher action wasn't an issue for him. He also never changed the strings on his bass unless they broke.
The 1981~1983 era is known as the Dan Smith era.
And so on...
The reference books are forgetting The Fender bass by Klaus Blasquiz who met Leo Fender and George Fullerton to write his book about these basses. The book was published a month after Leo's death and was, at the time, the best documented book about the Fender basses, with Leo and George approval.