In the original, the character is supposed to be "swarthy" and dark-haired, and the book itself implies that he may be of mixed origin, coming from an illegitimate union between a sailor from India, the Middle East, or a Black man. He comes from a port town where immigrants and foreign sailors are common, and other characters spend a lot of time fixating on his looks.
If they want to do it accurately, they should choose someone with ambiguous looks anyway, which they never do, so I don't see choosing someone who is clearly Black as any less accurate than choosing someone who is clearly white.
@ CbuttC, though.