I don't know how old you are, but I was in high school in California in the mid-1970s. The racial makeup of American then looked nothing like the racial makeup of today. I just now pulled my high school yearbook. My graduating class had 425 students. Of those, all were white except for (broadly categorized): 3 blacks, 14 latinos, and 4 asians. So, the original cast of A CHORUS LINE was probably more racially diverse than was the general population at the time.