[1969 GMC]

As far as the spindle nut goes, it is a hex type (not the one with the fingers, like an Eaton H052 or 14 bolt). At least mine was. I forget the size, maybe 2-9/16"?

The wheel bearings should go in OK, put a little bit of grease on them and make sure when you re-fill the diff you put in enough so that it flows down the tubes to the bearings.

I wouldnt change the carrier bearings unless you can tell they are FUBAR'd. Doing gear changes(or removing the carrier) in Dana axles is kind of a PITA because you need to acquire a housing spreader to get it to slip in.

The posi is a power-lock, and has replaceable wear clutches. I don't think you can really test these besides putting it under the truck and driving it some. Rebuilding them is fairly cheap, but you will need the housing spreader like I mentioned above.

As far as the yoke, IIRC it is not a press fit onto the pinion, but it is pretty tight. I seem to remember taking mine off with a hammer, but that was a while ago.

Other than that, you should be good to go.