Not necessarily. The spacer rings of the Meisterstück Solitaire Stainless Steel II are indeed platinum-plated, but they vary in production and can at times look considerably darker than catalogue pictures would lead one to expect. On top of that, sale photographs are frequently taken in poor light, in which stainless steel and platinum-plated parts throw back hardly any light and come out almost black. A dark ring on its own is therefore no grounds for suspecting a fake.
Other checks are more reliable, first among them the clip, which gives copies away in most cases: shape, crispness of the edges, the seating of the roller ring and the engraving almost always differ on fakes. Also to be examined are the star inlay in the cap top, the sharpness of the laser engraving on the surface, the ident number and the fit of the threads.
If none of these gives cause for concern, the pen is very probably genuine. A final judgement on photographs alone is never possible, however, which is why experienced collectors expressly offer their opinion in such cases without guarantee.