On the Charles Dickens of the Writers Edition the silver hallmark sits plainly visible at the lower end of the cap, while the word Pix is at the upper end beneath the clip. This arrangement is the rule and is one of the things taken into account when examining a pen.
There are, however, examples on which the two marks are placed exactly the other way round and whose authenticity the Montblanc service department nevertheless confirmed. A reversed arrangement on its own is thus no proof of a fake. Whether such caps were assembled the wrong way round at the factory, or taken apart and put back together incorrectly later, has never been settled.