Somewhere else I had read that on his father's side that there may have been slave traders, but that was based on the region from where his father was born.
Yes, of course.
Barry "Six States" Obama's father was from a group in then-British East Africa who frequently kidnapped black Africans and sold them to the brown Arabs for slaves. This was still going on as late as the 1940s.
The British had prohibitions against slavery, prohibitions which covered the whole Empire, but the British were also sensitive to the local cultures and mores of the colonials, and so while enforcing the law once in a while, generally let it go, so as to not upset people, as they did with the Hindus enslaving the "untouchables" of India.