Hi Martin,
Many thanks for commenting. I am still hoping others will as well even if the topic is a little "obscure".
About the Nupe possibility - I see what you mean. There is similarity in the line designs. I just thought Nupe were using more typical Hausa/Sahel style takouba scabbards.
Like on this link:
http://collection-online.moa.ubc.ca/...yearend=&row=5
Or in the image I am attaching - also showing sword with Nupe attribution.
I will keep searching - there must be some other example.
But it could be Nupe, typically we only see work from Bida I think and of course there were other Nupe cities.