Mitch,
No, this happens to be a K301 I'm overhauling for Kraig M. Both the rod and piston are non-Kohler, aftermarket parts. This failure was caused by metal fatigue. The oil return holes in the oil ring groove were cast-in square ports with sharp corners. Crack formed and propagated from one of these corners and eventually worked its way around the piston. It's considered a "soft" failure - piston fails and the engine gently coasts to a stop.