They are very much Uighur:-) And, of course, similar to the Uzbeki /Turkestani pichoks. Not a miracle: neighbourly and very closely related people. North-West China, Yengissar.
And very new, no more than 20 years old, likely much less.
For those of you who can read Russian ( Teodor, can you hear me ? :-)), here is a link to the Russian site with long and detailed discussion of these knives. And for the linguistically-challenged, the pics are plentiful.
Enjoy!
http://rusknife.com/topic/8629-ножи-суар/