1989 560SEL

I'm in the process of replacing my front wheel bearings. I've noticed some rust colored patches on the spindles and on the inside of the bearings (where they contact the spindle). Is this normal? I've attached a photo of one of the spindles. The car has 140K miles.

You can also click on this link to get a supersized image of the spindle (caution, 800KB)
http://http://dashdotcom.com/spindle/spindle-l.jpg