Brass Sextant a cheap copy?

This belongs to my brother, I’m tempted to put it in the scrap metal bucket but want to be sure before I tell him I think it’s maybe an Indian or Chinese copy and not worth him trying to sell. 4 and a half inches across, no makers marks. I think a bit may have broken off above the adjustable gauge which itself has wonky markers and numbers.
Ive had a look online but haven’t been able to find this exact one.
Any info please? Thanks.

 

This doesn't look like one of the fakes to me - maybe it's the pic but the scales look inlaid in nickel - are the fakes like that?
The fact you can't find another is probably a good indicator that it might not be a late repro.