Imperial German Reservist's Stein of Brunswick Hussar Rauche

Uncommon stein apparently owned by a one-year volunteer in the Brunswick Death's Head Hussars. This regiment (17th) took part in the Peninsular Campaign in Spain and Portugal against Napoleon, at Quatre-Bas just prior to the Battle of Waterloo, and in the Waterloo victory over Napoleon, at which time they were under the command of the Duke of Wellington. In the Franco-Prussian War of 1870, the regiment fought in the battle of Mars-LaTour, a French defeat that opened the way to an overall German victory. These battle honors are written around the circumference of the upper body of the stein. In 1867, at the integration of the Duchy in the Confederation of the North States of Germany, the Ducal hussars Rgt. of Brunswick received the Nr.17 of the hussar arm. In 1886, at the end of the convention with Prussia it was integrated into the Prussian army and lost its 'Ducal' title.
In 1867, the troop received a Kolback of the Prussian model covered in black bearskin with a large silver skull and crossbones prominently displayed on the front. This device appears on the stein just above the shoulder board.
One may usually determine that the stein belonged to a one-year volunteer because of the alternating color cord around the edge of the unit shoulder board as depicted in the central motif of the stein. The problem is that Reservist Rauche's dates of service are shown as 1900-03, three instead of the one year normally served by volunteers. I invite comments on this apparent inconsistency from knowledgeable collectors. The stein was purchased from a very reliable source and is absolutely original.