2000 Chevy Blazer axils?

Entirely different parts. There are 4 ball joints. One upper and lower per side. The axle shafts would only need to be replaced if they are bad or the boots were torn/damaged and got dirt in them.

If you're changing the ball joints you may also want to check the idler arm and the rest of the steering linkage as well. Remember that once the ball joints are replaced you will need to get the front aligned. That is why it is usually easier to change the idler, ball joints and tie rod ends all at once. But it's your choice.