My first thought was Baiwan also. The hilt shape is very reminiscent, as well as the turned up toe of the scabbard. Note, too, the suspension system with the two holes in the back of the scabbard through which the cord is threaded, which is a characteristic arrangement for the knives from several Taiwanese tribal groups.
Mid-20th C. seems about right based on the materials and general condition. Where did you find it, Rick?
Ian.
P.S. Rick, if you look at Sharrod Anderson's article on Baiwan knives on the old EEWRS site, the second picture of knives (bottom example) shows similar disks adorning the hilt. Ian.