Well, they definitely fit back together.  I brought this question up because I was installing 1.5" spacers and wanted to replace all the wheel studs for peace of mind.  Meaning I had to completely remove both shafts anyways, so I figured I would pose the question.  From an engineering perspective, as black diamond was talking about, it is an interesting point.  I feel whether intentional or not, the splines would shear/fail before the actual shaft reached its maximum tolerance for torsional forces, but who knows?  I have a blown head gasket and what feels like a collapsed steering column to sort out, plus an exo cage to farm out, so it'll be awhile before I can update.  If and when I break a rear axle shaft, I'll update with pictures and we can try to see if flipping sides contributed or not.  I will say I backed the rig out of my garage to clean up my mess, and it drove down the block, u-turned and re-parked just fine.  Now it's time to wire up the air compressor and plumb my lockers while I wait for my new head to arrive.