Hello Greg, and welcome to the forum! Thank you for posting this, as we very much appreciate those who do post and share items for discussions as well as those who join in with observations and contribute to discussions. While African weapons are not my usual field of study, I did do some looking to add some information pending the arrival here of the experts
This most unusual bifurcated or horned pommel seems key to this piece, and I agree it is not something typically seen with African weapons. The closest thing I can find similar has this very type of pommel, and is attributed to the Bali people from the Bamenda regions of Cameroon ("African Weapons", W.Fischer & M.Zirngibl, Passau, 1978, p.36). Bamenda is now the capital of Cameroon's Northwest Province which of course indicates its location in the country.
What is most interesting is that the poignard type blade on this is more of the style seen on weapons from Zaire ("Beaute Fatale", Brussels, 1992) as is the centrilinear motif with the use of repeated triple shallow arcs in a rocker style linear. The cuff type guard on the hilt which shoulders the blade is also well known throughout Central Africa Congo regions.
On the Cameroon weapons shown from these Northwest regions they are typically swords with blades which have curious bellied shapes in the middle and squared tips, far from this type of poignard blade. This simply suggests of course the diffusion of many of these weapons with the extensive trade and intertribal contact over many years. If the knife was collected just prior to 1900 it suggests possibly this was during the German colonial activity there during the late 19th century and the British administration which took place post WWI in which Cameroon and Nigeria were largely aligned together.
Returning to the interesting pommel style, this also quite possibly may have been associated with some anthromorphic and bifurcated stylizations from Zaire (Congo) along with many of thier sword tips which use semi circular shapes in bifurcated configuration. This might also align with the shallow arcs in the central linear design.
These are the best clues I can come up with, but the leatherwork and the comparison to this type hilt certainly suggest NW Cameroon, along with most interesting influences possibly derived from Zaire.
All the best,
Jim