Rear hub shaft tapered?

[RyanD]

I felt a little play in the rear wheels, so I thought I'd replace the bearings.  I started with the left rear.  The axle nut looked like it had loosened itself by less than 1/4 turn.  After disassembling everything, I noticed that the hub shaft looked tapered.  When I assembled the new bearing, the end of the shaft did not make contact with the inner race of the bearing.  I assume it wasn't this way originally and has worn down?

I haven't worked on the right rear yet.  It feels tighter and the axle nut is still tight.  I'm wondering if I should bother replacing the bearing or if I should just order new hubs and/or uprights.  I still have all of the original stock parts on the car with 5000 miles.