Waterman explained that:
The difference is in the Styling of the pens throughout the production of the Waterman Expert. Currently in 2013, the Waterman Expert III is the series of pens we offer and have offered since 2012. The Expert ( first version) was made up until 2001 & Expert II was made from 2002 - 2011. Neither the I or II are produced any longer. The only Waterman Expert Pen that is made is the version III.The difference is only in the styling details of the pen, the trim or the location of the Waterman Brand mark or country of origin mark. At Giftpens.com, we are leading distributor of Waterman pens and sell the latest factory fresh stock. When you see Waterman Expert listed, you will be getting the latest version which is technically the Expert III.