Many 79 4x4 ball joint questions

[sb400]

So I need a new upper ball joint on the driver's side. I have never worked on a 4wd axle before, so how hard it is to get to these things? I have a shop manual for an '82, mine is a '79 with manual hubs. Is it all the same?

Three of the four joints on my rig do not have grease fittings. One of the lower joints does have a grease fitting. Would it be safe to assume that the odd joint has been replaced? (that's not the side that is making noise).

Also, the joints appear to have big snap rings holding them in. Are they pressed in too, or would I be lucky enough to have them just come out when I remove the snap ring?

Does replacing the joints affect the alignment?

One more question...if it is a real chore to remove the steering knuckle, should I consider replacing the u-joint in the axle too? How hard it that? There are some clicking noises coming from the front end when the hubs are locked and the transfer case is in 2wd mode.

Thanks for your help from a 4wd newbie.