Is there a point you just replace the axles?

My Challenger has not been on the road since somewhere in the early '90's from what I can tell. Most of that time has been stored inside, but I have talked to a couple of guys that had similar sitting time on rigs and the axles/bearing had flat spots when they went to use them. I don't know if that is a common problem. I am considering a narrower rear housing with a spring relocation, so my thought was just do everything at the same time, along with the gear change and limited slip/Sure grip upgrade.

The other option is going with a Furd 9 inch, since I can get the correct length housing fairly reasonably priced, and everything is new. Guidance appreciated.