Anyone seen this on back of Receiver?

[jond41403]

I agree Eb for the most part but most of the hardness test dimples I have seen on carbine receivers are usually on the back of the receiver in front of the rear sight. I have never seen one where this dimple is above the tang but I thought maybe a first time for everything haha. Or am I confusing a hardness test dimple with a proof firing dimple?