Seems to be a regular occurrence for American Anal scenes to feature 1x BBC and 1x BWC...
Out of personal preference, I would much prefer to have both guys to be the same i.e. either both white, or both black. If we're talking about a gangbang using 3+ guys, then I wouldn't really mind.
Not sure what other AA fans care for, but I'd rather see 2 BBC performing DP.