So I pulled my axles today and there are two grey plastic rings that were at the end. I have read a couple write ups on changing axles but none of them mention these rings. They are a little beat up. What are they?

 

I swapped those over to my new fronts when I changed them. I think they are pebble/stone caps to try to keep that junk out of the axle tubes. They aren't tight enough to be dust caps. I figured that Jeep put them on for SOME reason so I moved 'em to the Alloy USA's

 

If you are talking about the rings that look like washers they are there to center the axel when it is installed at the factory so it doesn't mess up the seals

 

Yes. In the parts book, they are called "Guide, Axle Shaft". They are just outboard of the seals.
Part number 68017185AA