I wouldn't worry about history/name messups. Most of the second generation instructors in Korea (following WWII) didn't know the background of their art. Over the past 10 years, people are now beginning to really research and find the background and history.
Beginning in the late 1960's or early 1970's, Lee Nam-sok became a part of General Choi's organization in some capacity - though I don't know what. Lee Nam-sok, really quit training in the 1960's and became some sort of businessman. General Choi brought Lee Nam-sok to try an recruit my instructor, GM Kim Pyung-soo, into the ITF in 1973. General Choi figured since Lee Nam-sok was GM Kim's first instructor (1952), this would be a good way to persuade him to join. He also brought a nice piece of caligraphy he made himself as a gift. GM Kim turned him down.
Considering the karate forms included in General Choi's 1965 TKD book (if he actually knew the forms) it looks as though he obtained some Dan-level grade in karate. But, there is also the possibility that he obtained those from the Chungdo-kwan, then wrote the book.
R. McLain