With the vast majority of surplus rifles, it's impossible to say just where they were, what they saw, what they were a part of. Once in a long while, we can obtain something that we can almost-certainly know about; in my own collection, my "LaTorre" Ross (formerly 16 B'n CEF) is the specimen in point.
Only VERY seldom do we find one that can be even partly truly authenticated, and, even then, we never know the full story. I have a French revolver that I KNOW was used in close combat...... just can't prove it because the man who owned it is long gone.
But this is all a part of what makes this hobby unlike any other.
Handle them ALL with respect....... and never let the condition of a barrel tell you that a rifle never saw action. It only takes ONE round to win a VC..... if you place it right, at the right time, in the right circumstance.