So Hombre, since you are asking for our thoughts, why not share yours?
Its discussion, not poker
I have had one of these for years, but have had no further notes other than it is a larger than normal janbiyya form from Hejaz, known as 'sabaki' as noted.
What drew me to this exemplar was that in research on Sir Richard Burton, in his 1853 account " A Pilgrimage to El Medinah and Meccah". In this Royal Geographic sponsored journey, Burton took the great risk of entering these Holy Places disguised as a Pathan Holy Man (not sure of the exact complexity of his identity).
The narrative was published in 1857 , and in this there was a line drawing of one of these, and other sources noted it was a sabaki, the association with Wahhabite followers.
In the photo shown in earlier post, the man and wife are Harb, whom were dominant tribe in Hejaz when Burton journeyed through, particularly surrounding Medina.
As noted, there is no reason this form should be attributed specifically to Wahhabites, as it seems a form that was notably present in Hejaz and to whatever tribes or followings present in those regions.
As I have no specialized knowledge or resources beyond what I have shared here, I'd very much appreciate the observations of those who do on this example.