First you'll need to know the difference between knife tang's....borrowed from the web..
Knife Anatomy 101: What is a Knifes Tang?
credit to CTD Blogger
You see it in the descriptions of many types of fixed blade knives: full tang, half tang, rat-tail tang,yet what is a knifes tang?
The tang of a knife is the projecting shank, prong, fang, or tongue that connects the blade with the handle. There are many different types of tang, depending on the style of the knife and the construction of the handle.
Full Tang
The term full tang means that the knife/sword is one solid piece and the 2 handle pieces are pinned on to the blade, one on each side. This is the strongest of the tang types. Half tang knives go the length of the knife handle, but only half the width of it.
Full Tang
Push Tang/Stick Tang
This is a partial tang that is pushed into and secured to the handle with glue or epoxy. They usually come in full and half push- half only going into half of the handle, while full being pushed in the full length of the handle.
Push Tang
Rat Tail Tang
In a rat tail tang, the tang narrows as it goes through the handle and is either threaded at the end or is welded to a piece of threaded rod. A bolt or threaded pommel secures the blade to the handle.
Rat Tail Tang
Next removing the rust will also dull the damascus pattern regardless of quality..up to you
And who knows were it came from, most likely .....