I have taken my digicam PM2 and GB apart. PM2 was to thoroughly clean and polish pivot washers and adjust everything so it was centered,smooth, etc(I bought it used). GB was taken apart so I could force a patina on the blade and not muck up the rest of the knife. My guess is they can tell by looking at the factory loctite as well as if any internal parts were messed with (scratches, etc).