Fwiw, Clarence Major's book "Juba To Jive-A Dictionary of African American Slang" {Penguin Books, 1994; p 313} has the following entries:

Nappy adj {1800s-1950{ kinky, wooly, usually said of someone's hair

Nappy edges n. {1870s-1940s} brittle and broken hair along the hair line

Nappyblack adj (1960s} very African looking."

-snip-

Fwiw, I've never heard the phrases "nappy edges" and "nappyblack".

In "Juba To Jive", Majors also has these entries:

"Good hair n {1880s-1950s} straight or almost straight hair {a concept that began to disappear in the early sixties with the renewal of black consciousness}, silky straight hair [p. 207]

[Hair] Going back v {1900s-1970s} processed or straightened hair returning to its natural state..." [207]

-snip-

I confess that I don't understand the system that Major used for the dates he gave. I think that the dates given in brackets are when he and others found documentation of these words' use. Or maybe these dates are when Majors or others thought that the words were most popular. But perhaps the end date is when Majors believes the word has stopped being used. [???] I can testify to the fact that in African American communities in 2007 the phrases "nappy hair", "good hair" {and its opposite "bad hair"}; and "hair going back" are still very much in use by men, women, teens, and children.

Majors ascribed various sources for the slang words & phrases in his book, but the acronym system that he used for these sources is extremely hard for me to decipher.

I did figure out that one source that Major used for the word "nappy" which he gave as SL, RJON was "Longstreet, Stephen "The Real Jazz, Old and New: Baton Rouge: Louisanna State University Press, 1956.

Also, Major cites that same book for the "nappy edges" entry. Among other citations, he gives this "Btisaje Sgabge, "Nappy Edges", 1978.