Spindle / Axel Difference

I pulled the tires today in prep for refinishing the wheels and new tires.



I noticed that the front spindles have grease deflectors (Group A3-5, part no. 40172, pg 5 MPC) and the rear axels do not.



Why?? Is there something very different in the way the seals work??



Also, the fronts have sepage of grease and the rears are clean. Is this normal as well.



And if one is cleaning up the drums, is it OK to paint them "suspension" black? Or should I just have them blasted?