its most likely handmade. Even the "real deal" khuks by Himalayan Imports are handmade, i.e. a bladesmith literally sits down on the earth and hammers/forges/finishes a blade with only the most rudimentary power tools.
The devil is in the details. The hard part of making a khukuri (or any knife, really) is in the heat treat. Well made khuks go through a pretty strict process of pouring water over the edge at JUST the right rate to end up with a cutting surface that is tough yet durable and holds an edge. Most of the tourist stuff are left soft as the process isn't really necessary for a wall-hanger.
You could try taking a file gently down the edge. If it bites through the recurve, then skips about 3" from the time, then bites again, it probably was heat treated.
If could also cut up a lemon with it if you don't mind the edge getting a patina. The lemon juice, if left to sit on the blade for a bit, will mark out the pattern. If your khuk has been heat treated, then you will notice a different intensity of gray coloration just south of the tip for a few inches. This is the hardened "sweet spot" made to do the heavy cutting. The rest is softer to absorb impact.