In my experience, it's covering their ass.
I doubt it shows anything(it's a 223).
It's a used gun, something will be marked on it, or in some way you will be able to tell that it's used, but I doubt it has really seen much use at all, and if it has?
Like I said, it's a 223. If it has 4k rounds through it, should still have that many more.
I have purchased several through the gun library, I found they made them sound worse than they were.
I don't think I have gotten more than 5 guns through them tho, and it's probably more the individual locations and how they decide to describe them.