Actually the point is about the evidence presented.
It is not conclusive, in my opinion, and raises more questions than we will ever have the answers to.
The photo from AP was certainly not of a pristine round (compare to RobVG's photo). On the other hand, it is possible that the round was polished before shown to reporters (my uncles typically did this with WWII relics, eg.).
We do not know the history of this round. All we know is that according to this lady, it came out of her bed. Maybe, maybe not.