I work with the Family History department, with many friends in the Church History department. I asked one of the historians about that story. He told me that it is documented in the archives. The story was related by David Patten. Pres. Kimball wouldn't have used the story if it hadn't been documented. We don't know the whole story of Cain. The account in the Book of Jasher is interesting BUT . . . it contains many Hebrew myths, the veracity of which can't be absolutely proven. So we take that account of Tubal-Cain with a dose of caution. To illustrate, Naphtali was said to be so fleet, and light of foot that he could run through a field of harvested corn, and not damage one sheaf. That's a neat story but how true is it? We don't know. So we need to be cautious about reading apocryphal books. I read them and they really help me to understand the scriptures, but . . . again . . . I have to use caution.