At North Texas State University, 1964, splib was the common word for black African Americans used by the jazz crowd. Gray, or gray dude, referred to whites on a similar level. These were in common usage among many civil rights activists as well.
I did not perceive it as derogatory at the time, more a hip code-word among the jivers (those speaking jive-talk).
That splib band had a lot of soul; the gray dude couldn't keep up.