The black paint on those pipes will come off. It's just a matter of if you do it before putting the machine together or cleaning it off the bearings as they wear it away in clingy little chips that get evERYWHERE... ARRRRGGGG!!
Sorry. If you couldn't tell, I did the latter. Hindsight being 20/20 I would have saved myself the aggrevation and done it BEFORE putting the machine together. However there is always the optimistic side of me that sees the part of the pipe the bearings don't ride on as protected from the elements in my dry and insulated garage.
The other thing I noticed is that the bearing will ride smoother if you remove the coating. I think there is some sort of javelin toss going on over at my local Home Depot as all the pipes were beat up and missing paint in spots. Took me longer to line the bearings up with a clear path on the pipes than would have taken to clean up the pipes in the first place. Oh well, lesson learned.