Hi Richard,
thanks for the additional info
As to the cotton/canvas backing....It probably depends on the 'finishing' material. I think the idea of the backing is to 'smooth out' the surface so that finer fabrics appear smoother. Velvet would not show any minor imperfections in the woodwork below.......I am not suggesting there are 'imperfections' in your own scabbard

(it actually looks very nice, the fittings set it off nicely...but I do not think the wood would have been left 'uncovered' originally....unfortunately) Glueing seems to be the normal method, however I do not know what sort of adhesive would have been used originally. Most modern 'contact' adhesives should be OK....but I would recommend that you 'seal' the wood first by applying a coat of the adhesive to the scabbard and letting it dry.....and then use the glue to bond the fabric 'coating'. I have one velvet covered scabbard which has the 'seam' ( folded edge) hidden beneath some decorative 'edging' but do not know whether this is traditional.I want to make a scabbard for the khanda but would like to find a 'period' looking covering for the wooden core......and the 'suspension' rings/mountings will have to be fabricated.(again I will have to find examples). I really like those on your scabbard.....sufficently ornate without being 'over the top'.
One other thought....the scabbard furniture...was it fixed/riveted to the scabbard or bonded/glued to the scabbard?
Regards David