ifs44 axle spindles question

[Rockhauler]

I have several spindles from trucks of multiple years I've scraped about half have a recess where the thrust washer sits and the other have there is no recess. I find it hard to believe the ones with a step are from wear since the step looks to be the same depth on all of these spindles. Were the spindles changed through the years or am I just seeing worn spindles? The spindle on the left in the picture shows the step I'm talking about.

[viven44]

If I'm not mistaken the "odd one" is missing the bearing...

Edit:
Nevermind you are asking about the recess... yes that is odd.

[salans7]

A change like that was probably just for tolerances.

I've seen quite a few different spindles over the years, so I'm not surprised. I believe there were even 5 lug spindles at some point between 1980 and 1996, although I can't remember for sure.

[Rockhauler]

Guess this might of been Fords way of making adjustment for if things were to tight of tolerances. I'll check for end play  after assembling the wheel end.