I have wondered that too, but if neither candidate had name recognition, I wonder how race could have figured in.
OTOH, race could have been a matter for word-of-mouth discussion of who to vote for among the Rat faithful that show up for primaries.
The faithful probably also trusted that the S.C. Rat Party apparatus had vetted the candidates minimally, so what did it matter, just vote for the black guy. Sort of like people trusted that party hacks somewhere had vetted Barry.
Well, I don’t think anybody was going to believe “Vic Rawls” was a black name, even if they weren’t sure that Al Greene was black.
I think that if you did random tests, you’d find that “Al Greene” is a much more ‘positive’ name than “Vic Rawls”, and so people would be drawn to vote for that name over Vic.