Hi TVV,
Thank you for posting this! It seems you are aware of the discussions a number of years ago that were concurrent with research I did on these. Much as with the Kurdish/Armenian vs. North African controversy regarding the so called Black Sea yataghans (which turned up being Laz Bichagi with some very nice research work by Ariel), the controversy of these being termed 'Zanzibar' swords vs. my contention they were from Morocco stirred considerable debate.
Your example appears a 20th c. example of the dagger termed s'boula according to references in the work of Charles Buttin. Apparantly the 19th c. examples of these had straight needle point blades with the distinct I shaped hilt and Sir Richard Burton illustrated these in his 1884 "Book of the Sword", captioned as 'Zanzibar swords'. Apparantly this identification was taken directly (even the illustration) from an earlier work by French arms writer Auguste Demmin. The compounded misidentification was noted by Charles Buttin, the famed French scholar and author on antique arms in his catalog (publ. 1933) where he notes that Burton had used the Demmin reference for Zanzibar. Buttin identifies these distinctly hilted weapons as s'boula from Morocco, an attribution he was well qualified to cite as he had lived in regions in Morocco for considerable periods over 40 years.
This was the thesis for a talk I presented several years ago in Baltimore, and where the alternate suggestion occurred that these were in fact Ethiopian!
It is true that these do appear in groupings (though rarely) of Ethiopian weapons, and I believe Anthony Tirri had one with Amharic markings. It is my opinion that the examples found in Ethiopia were anamolous and probably appeared there via trade routes that passed through from Saharan regions, and of course likely connected to those from Zanzibar and inland.
The discussions on these were excellent on the amazing diffusion of ethnographic weapons, as well as certain misattributions perpetuated on certain weapons from earlier works. As I once heard, "...the thing about history is that it's always changing!". Pretty much the same on weapons study as research continues
All the best,
Jim