Are my struts going out?

[truwarrior]

While installing my upper control arm bushings in the rear. I noticed a decent amount of black goo (rather thick almost tar like) towards the bottom of the springs and a few smaller spots on top of the upper control arm. Is this stuff from my struts? I have Koni yellows in the rear. The ride appears to be ok although the inside of my tires do have some wear which I'm in the process of getting resolved...