Like said, the greater portion of the time the bearing spinning takes the rod ID out. If you use it over the rod quickly spins again, the bore has been yielded. I have seen maybe 3-4 over the years that one could be reused but not common and not the norm at all. Hope you're looking at the crank in the same way, often they scrap too.
You don't 'spin' pistons, you spin the rod bearing.
(edit) I see you are already looking for a crank..................