Hmmm...Out of my comfort zone to usually reply on such pieces, but my first impression was that it was a fantasy-type reproduction of a Spanish main gauche. Old, certainly, but odd and exaggerated in construction. I can pretty safely say it is not a modern fake just due to its aging. Not a Historismis piece from the Victorian due to its unconventional styling. Then I began to suspect it might be a Spanish colonial knock-off of an original main gauche, which, if true, is pretty cool and desirable!
As you probably know, the Spaniards in the American Southwest were pretty hard up for supplies, weapons, tools, etc, and had to make do or create their own items to survive. This trend extended even to the use of native materials to create their own style of furniture and fixtures. The point being, colonial Spanish had it's own style and design, breaking away from the traditional patterns of Europe based on what they had and what they could creatively come up with. I am a huge fan of the designs, furniture and weapons from the colonial era. Many of their swords had makeshift hilts made by 'artisan' blacksmiths, recycled sword blades, reused hilt materials from other swords, etc. Thus, each piece could be rather eclectic. The hilt work on yours (to me) resembles the cut-out metal patterns similar to later Mexican espada (which I often compare to their spurs as well).
So...it could be Spanish colonial, but let's hear what other folks think. I don't think the Chinese fakers would create such a one-off, folk-artsy piece to try and fool anyone-
Mark