I'm no expert.
But,
I have lots of thoughts.
Even some truly old khukuris are basically
tourist junk from that era.
More likely for India produced khuks, more tourists,
than for real Nepal produced.
Even in the late 1800's,
the "civilized" world spawned
lots of tourists into the Middle East.
Shopkeepers and street sellers would have
realized that cheap-made gave them a better profit.
Beyond that, its easy to lay a modern khuk out
in the sun and weather for a short time
and age it significantly.
Or there are other methods not too involved.
I've seen several modern khuks (Atlanta Cutlery style)
sold on EBay as old "style" with the implication
that they were old.
I'm very hesitant to give money for 'old' in a description.
Research what makes a good khuk. Here, and links found here.
It boils down to design, finish, and proper hardening.
(Do a search here on 'harden' & 'temper')
You'll have to handle many blades, and look at even more online.
I don't trust myself to be correct when it comes to buying
a 'found' khuk. Not enough experience. I would recognize
(I think, hope) an excellent khuk or a horrible khuk.
But couldn't necessarily tell the difference between
better average and worse average grades.
And I wouldn't even try to guess age.
There are lots of real Gorkha khuks out there.
Khuk designs have long been made for various military and
police forces. Some for using and some mostly for show.
It's only in, what, the last year or two that the British Gurkha
regiments were disbanded.
And Ghorkhas are still employed around the world
and they still carry khuks.
Those khuks are very good usable utility blades,
but I think probably not THE highest quality.
I depend on Himalayan Imports and this forum to give me
quality goods and info.
When you get a picture up you'll get some quality opinions
on the probable source & quality of the blade.