The last one has the "green cup" attached to it. That is the "outer race" and is actually the axle shaft that fits into the front axle housing. I didn't look too closely at the first two, but they do seem to be similar. Maybe they are different lengths? I know that there are a couple of threads rolling around here regarding the front axle shafts and their associated part numbers.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless