More like someone broached the ends I would think. It doesn't appear to be an impact style socket, purely due to the coloring, but its a cool idea regardless. I would talk to a local machine shop or if you have any machinist friends see if they could make something similar. That is actually a relatively common practice in other applications, more so plastics than metal like that, but an interesting concept nonetheless.
#oneleggedproblems
-=Sam=-