Thanks ! I will use english to answer your questions as this is an english-speaking forum.
You are right to say that on most kindjals the handle and the scabbard do not slot, at least as long as they are not covered with metal fittings, they just juxtapose like this :
But when the handle is metal-covered, the metal fitting at the throat of the scabbard usually slots into the metal fitting of the handle. An enlarged ring of the handle fitting allows the scabbard to fit inside it. You can find many examples in the forum :
http://www.vikingsword.com/vb/showth...hlight=kindjal
http://www.vikingsword.com/vb/showth...hlight=kindjal
The scabbard is covered with thinned goat skin (which is commonly used with most of the genuine kindjals)
Regards,
Bernard