As a person who talked to many Gurans(the name that they actually call themselves.) I can confirm that they are indigenous to Africa. People must understand that Africans are very diverse and you have many people with loosely textured hair like the Fulani, Afars, Beja, Dongola and etc… All of these groups I mentioned have been in Africa for thousands of years.
The problem with today's modern generation is that everyone is supposed to be indigenous to one place, and one place only, but that is not true. You have Bejas who are in Sudan, Eritrea, and Egypt. The reason why they are in all these places is due to the fact that they are nomads they travel and set up shop in many different places. Same thing with Somalis who had vasts amounts of land piercing into other borders in Africa. This same logic can also be applied to the Guran who also are indigenous to Niger, Chad, and Southern Libya