That is indeed the intention: one point of the star is meant to line up exactly with the clip. Montblanc attaches a good deal of importance to this alignment, and even applies it to the star set into the floor of its boutiques, which turns one of its points towards the entrance. In series production, however, the rule is by no means reliably observed. Because the cap top carrying the star is screwed into place, the final position depends on where the thread comes to rest; stars sitting off-line are therefore a regular occurrence, occasionally even on limited editions.
A star at an angle is thus neither evidence of a fake nor a defect that devalues a pen, but simply a manufacturing tolerance. Equally, perfect alignment is no proof of authenticity. Anyone with doubts about a particular piece should go by features that actually carry weight – the finish of the cap ring and the engravings, the material, the nib and the mechanism – and not by where the star happens to sit.