5 Lugs?

No you don't need to replace the axles. Been a while since i had an axle out, but if i remember correctly the bearing rides on the axle directly with no raceway.
There are instances when the bearing cuts a decent groove in the axle from being bad so long, i think there are ways to fix that. Never had it happen, so i'm not totally sure.
One of mine was a little worn back in the day, but it has been fine for 17 years so...

In my small inside voice "I broke a stock axle with a stock motor and a 150 nitrous shot w/slicks". In all honestly I think op will be fine as long as he's not using slicks.