Hi !
There is some good information in "Essai sur l'épée des Touareg de l'Ahaggar" by Morel, however, the article is in French. I will translate the relevant extract for you, but I won't be able to do it until tomorrow, I think. In the meantime, here is some relevant screenshots from the article.
I can already tell you that the scabbard is made of leather only (no wood core), and that it is not stitched but glued. But I sadly don't own one with a scabbard myself.
Is the takouba you're talking about made by Da'Mon Stith by any chance ?