Honestly: somewhat. American blacks have no idea what their actual ethnicity is, and would have had no way of recording it. However, different ethnic groups clearly had different outcomes in Africa. Importing Nubians probably isn't that big a deal, but importing Zulu is fucking crazy.

The real problem here is that those ethnic identities were wiped out and they were instilled with pre-Anglicanizatoin Ulster Scot culture instead, which leads to basically no benefit whatsoever. You might as well have imported the Zulu at that point, because you would have been selecting for poor cultural indoctrination. Worse, adding the dependency system on top of it multiplies the problem.