I have been following this tread closely. I now own the Tibetan/Boan knife that started this discussion. The scabbard is different than Tibetan knives I've seen in the past. Perhaps the scabbard design is the key to determining the origin of this knife? Tibetan scabbards are usually fancy and a very different shape.
Here are some pics of a couple trousses that I own. Note the Mongolian has fullers, the Chinese has none. Can someone translate the chop mark on the Mongolian blade?
