Islam had most of Northern Africa by then and there were communities in the West as traders had been proselytizing. It’s a sure thing that a number of Muslims were among the slaves. But it’s irrelevant since they didn’t bring their culture with them for the most part.
FACT.... islam did take on most of nothern africa, but the desert limited their expansion to the south and west.
Sure there was a minor group of traders that did try going there but if you recollect there was nothing there to trade. The Portuguese were the first traders to the pepper coast... or the grain coast back in the early 1500s. They set up trading posts with the main objective of taking gold out. Africa has long been a place economically backwards without any organized farming or commercial enterprises. Later , they too took to trading in slaves.
The portugese were largely a christian lot..