If you can tighten the bar down and lock it up so you cannot slide it in or out by hand, then it's still good. Don't worry about it.
We had our friction sway bar for about 10 years and used it for thousands and thousands of miles. It still worked great... until one day, when I tried to loosed it and the tightening handle literally broke off, still tight! I was devastated. How do I get this thing off now? I went ahead and unpinned both end and then was able to move the rig slightly, enough to take the pressure off the little balls, and it slipped right off.
Well, we were heading South the next trip out and went right by Camping World South of Indianapolis. We swung in with camper and all, picked up a new one, I didn't have to change the little balls either, and then slipped on the new one.
Bottom line, if you still have friction, you don't need a new one... unless you break the handle!