Firstly, verify the box and availability of service guide with warranty.
The booklet will not only give you procedures of maintenance and servicing, but the warranty along with the date of purchase and authorized dealer mark.
Check the individual serial numbers written on the ring.
A Starwalker Fineliner can be refilled with Rollerball refills but never comes with it. Don't doubt on this basis though. Your seller might just be generous! :)
It has a MontBlanc engraving and should read GERMANY under the clips.
Another interesting experiment is the flashlight test.
Shine a strong beam of light through the resin dome on top and it will glow letting the light pass through. The fake domes are generally semi-opaque.
And most importantly, only buy with authorized Montblanc dealers.
Pen Boutique is proud to be one of the few authorized Dealers for Montblanc.
Get 100% genuine products and 100% satisfaction . www.penboutique.com