Montblanc never built a Bohème with a four-colour refill. The ballpoints of this line work without exception with a single standard refill; listings that promise a multi-colour mechanism are either describing a different model or are simply mislabelled.
The words Limited Edition, applied to a red Bohème ballpoint, are as a rule sales talk too. The red Bohème was a regular catalogue model, not a limited run; it was merely taken out of the range at some point and was no longer available in 2016. A model being discontinued makes it neither a Limited Edition nor automatically more valuable. Genuine Limited Editions are announced as such by Montblanc and documented; visible numbering on the pen itself, however, is not obligatory, since special and collector's editions in particular often carry no number at all.