Maybe they had a mix of muskets, taking anything they had in stock?
Nope. The 2nd Nassau was not a new regiment and it had no shortage of muskets. But during the Waterloo campaign it was part of the NL field-army, and in May it was ordered that all should be armed with British muskets because having two different calibers would simply be too confusing, logistic-wise. Goedecke, Colonel-Brigadier of the 2nd, refused to give up his muskets because the muskets were property of the Duke of Nassau, not of the Dutch Government. He eventually agreed to the change after he was promised that he would not be held responsible.
Maybe it's just me, but they look better with white pants than they do with green ones.
Nope. Just you.