Hi Lew,
I've attached a couple additional photos below of the scabbard... the wear and patina IMHO seemed to indicate a bit more age. Tirri shows five "Wahabite" jambiyas, of which three look nearly identical to mine, all identified as "late 19th/early 20th." Bad information? What stylistic differences would mark an older piece? Also, I was under the impression the ridged blades (no ground fullers leaving a ridge vis stock removal, but a forged ridge) were good indicators of age?