Yes, the original 6239 was supposed to be called the "Le Mans" and not the Daytona. There are several stories of why Rolex decided to change the name but I don't know if it is universally accepted that one is more accurate than the others.
Another thing, the Cosmograph designation for the Daytona models were made as Rolex anticipated having these models tested and ready for NASA to be used in space but that was never the case and hence, the Speedmaster won out and was chosen. π€·ββοΈ