The 149 version with the silver bands (aka rings) on the cap are specific to the celluloid 149. This version was produced in the 50's and when the celluloid 149 was transitioned to the resin 149 the silver rings were replaced by gold plated rings.

The 50's celluloid (Silver Ring) 149's may be (IMO) the greatest fountain pens ever made. They included the absolutely genius Montblanc 2 stage "telescopic" piston filling system which, sadly, Montblanc had to abandon when they transitioned to the resin 149. Reason(s) why?? 1. They were too expensive to manufacture at the price for which MB wanted to sell the pen and 2. Not just any pen repair hack could service them...they required someone with specialized knowledge, skills and training.