HI Charles,
I've long followed this wonderful sword and it is certainly in the right home now.
I've also kept this reference in mind for years and this is the right place to include it as a specific example of 17th C. North Africa/Ottoman workmanship. The attached images from a German private collection show a sword with similar enamel work, with a different style grip, but with the classic Mediterranean trade blade, often attributed to Genoa (though I think Mediterranean is the best we can do at this point without specific evidence of an Italian city production).
I would certainly think this sword has little to do with the East African style of sword, lso referred to as a nimcha, and even less with the swords originating from the Southern Arabian peninsula, a (interestingly that is the terminology along the west coast of India as well for a sword indicating the trade routes the word, if not the form traveled on, though there are Hyderabadi hilt forms that are similar to the East African, or rather Indian Ocean style of hilt).
However, the Bukharan enamel connection is definetely a possibility as I've seen this blue and green enamel work on other Ottoman daggers, including on sold by us some years back over gold, see below:
http://armsandantiques.com/beautiful...r-dagger-id851
And also another found in the Wallace Collection. I think the enamelling is most likely early 18th C. Ottoman workmanship, likely on order depending on where in the Empire, or associated states, it went.