How tell what kind of rod bolts...

[kenikh]

I just pulled a crank, a very interesting crank mind you and am trying to figure out what kind of rod bolts it has. They don't quite look like the stock ones I've seen (the nuts are bluish) and the rod bolt tops read "versus 12.9".

I'll post pics later, but is there any easy way to tell if these are stock or aftermarket? The reason I am curious if they are aftermarket is that there appears to have been balancing machine work done to the rotating assembly. If the builder went to this kind of trouble, I'd almost imagine he'd go all the way.