The pin definitely holds something in there and roller is as good a guess as any. Perhaps it is worn down. No serrations on the roller that I can see, but the tool is made of stamped steel and not forged like most of the Diamond Tools I have collected. Have not buffed it in search of a logo yet either. Maybe the next step. Side view photo coming up....and no logo.....as soon as my nose hair needs trimming, I'll see how the chrome tool works for that job(TMI)
DM&FS