in some way unused modern arms are more difficult to judge.
In Nepal 9 or 10 years ago old army kukri were sold for 4 times the price of a modern shiny lookalike piece, not for collector value just if it had lasted 80 or 100 years in a village you knew it was good! the locals would trust in it, The said new ones can look amazing then break , obviously due to poor steel tempering near the tang, poor steel, stress risers on poorly ground tangs etc.
If a knife or sword is to be used for real it should be tested, new or old.
The blade should be smacked at maximum impact into a thick oak {or equivalent.} plank {not the log end.} 3 or 4 times from edge, both sides & spine. {Safety gear may be needed.
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If its ok, not bent broken or grip become loose then its probably ok to use if your life depends on it.
There are further old ww2 Gurkha tests to fine tune stuff for higher finesse, but the basic smash it & see from all angles lets you know whether it a user or not.
spiral