I'm not an expert, but why would be a broad blade be a sign of earliness? I mean, it doesn't seem like as if it'd be compensating for weaker material. And as eastern armour was never as widespread or used everyday, or covering-all, a more cut-oriented swordplay (even as it's not a sword) could remain in fashion for ages. I may be terribly wrong on this, though, as I don't really know eastern fighting methods, and my sources, as I mentioned it before, are quite limited.
Why would it be a jambiya? I was told that "jambiyas are curved, tapering blades for slicing and for curved thursts, or for korambit-like usage". And this blade is surely a fierce cutter with inferior thursting capability. Was my source incorrect, again?
Sorry as my post contained more questions than answers, but I'm studiing this area (eastern weaponry) for less than half of a year.