Plates with Courland troops on Dutch service 1672-75

By occasion I found two plates named as Courland troops on Dutch service in 1672-75. In 1672 Duke Frederick Casimir of Courland agreed to provide a Foot, a Horse & a Dragoon regiments on Dutch service (all troops were maintained by Friesland). I've written about their colours and standards earlier (link). Unfortunately I don't have any info about their uniforms & can't give any comments about the plates. They could be a fake.