We do see black Moors represented in Alfonso X's Book of Games (1283), and since they are being waited on while they play chess, they are obviously not in a position of "submission":Everybody influenced each other, especially when we talk about Mediterranean world (that explain why so many civilization flourished in that area)
Apart the meso-American (the reason why they were so limited), no civilization built
The problem is that we don't see any blacks among moors in medieval spanish representations and other miniatures (apart in rare occasions and always in a position of submission). We can establish that black slaves were quite common into muslim societies since the VIII century. So yes, there were blacks among moors but mainly slaves. The word "moor" itself come from Mauretania, an ancient kingdom from the ancient time. But greeks and romans didn't note any black presence in North Africa. The blacks that ancient European encountered at these time came mostly from the eastern part of the African continent (Nubia, Sudan, Eritrea, Ethiopia).
An interesting point : the majority of black representations into the moorish-muslim world come from the paintings of the 19th century ?
All of the other "Moors" depicted in the illustrations for the Book of Games are not black, but these particular ones are clearly black Moors.
There is also a reference to black qaids (commanders) among the Almohads in Ibn Khallikan's biographical dictionary (written around 1274). It would be hard to trace the reference down again, so I won't do that just right now although I might be able to later. There is an 1842 English translation of Ibn Khallikan's biographical dictionary available online and that is where I first saw this; of course the use of some black soldiers by both the Almoravids and (to a lesser extent) the Almohads is well known, and the book Medieval Muslim Government In Barbary (1958) by J.F.P. Hopkins discusses some other instances where black soldiers were used, but I had not seen that reference to black qaids/commanders among the Almohads until I stumbled upon it in that translation of Ibn Khallikan's biographical dictionary.
There was also a black poet and man of letters, Abu Ishaq Ibrahim ibn Yaqub al-Kanimi, from Kanem, at the court of the Almohad ruler al-Mansur (and he wasn't a slave). Part of a poem that he recited to al-Mansur is quoted in Yaqut's "Dictionary of Countries" (1224).
There is also a reference to there being some black troops among the 711 army of Tariq ibn Ziyad in work written circa 950 by Ishaq ibn al-Husayn, though of course whether that is really reliable is uncertain since the claim is made two and a half centuries after the event.
There is also a reference to leaders from the Ghana empire visiting al-Andalus in al-Zuhri's Book of Geography (1137).
Also, it would be misleading to suggest that any blacks among the "Moors" would necessarily always be in a position of "submission" when one takes into account the relationship between Zafun/Diafunu and the Almoravids described in Yaqut's "Dictionary of Countries" (1224), where Zafun/Diafunu held a dominant position in their relationship:
"Zafun is a vast province in the land of the Sudan, near the Maghrib, and adjoining the land of the veiled people (mulaththamun). The people of Zafun have a powerful and redoubtable king. He has a capital, which they call Zafun. He leads a nomadic life, seeking [pasture] in places where the rains have fallen. This used to be the way of life of the veiled people before they took possession of the Maghrib. The king of Zafun is stronger than the latter and more versed in the art of kingship. The veiled people acknowledge his superiority over them, obey him and resort to him in all important matters of government. One year this king, on his way to the Pilgrimage, came to the Maghrib to pay a visit to the Commander of the Muslims (amir al-muslimin), the Veiled King of the Maghrib, of the tribe of the Lamtuna. The Commander of the Muslims met him on foot, whereas the [King of] Zafun did not dismount for him. A certain person who saw him in Marrakech on the day he came there said that he was tall, of deep black complexion and veiled. The whites of his eyes were bloodshot as if they were two glowing coals, and the palms of his hands were yellow as if tinted with saffron. He was wearing a cut garment enveloped in a white cloak. He entered the palace of the Commander of the Muslims mounted, while the latter walked in front of him." - Yaqut
Zafun/Diafunu was a Soninke state.
There were also some non-black slaves among certain black kingdoms/empires in the western and central Sudan, if we go by medieval Arabic sources.
I don't have much interest in the question of the racial composition of the "Moors" that were in Iberia though I agree with general consensus that the vast majority were not black, but it is not necessary to imagine that because they mostly were not black that any black "Moors" there were slaves. One should seek out additional reliable information about these topics where possible before jumping to conclusions.