According to Heath (and Gladiator Miniatures) Pruss and Lithuanian infantry were dressed and equipped similarly. Heath notes Polish reconstructions of 12-13th C Lithuanians that are identical to the Pruss depicted in Armies of Feudal Europe.
However, he does not state whether they also preferred white fabric for their clothing.
Minor point and as they have darker brown or black hair it does provide a point of difference. But it would be nice to know if there was more color in their costume.
On a bit of a tangent, given the Teutonic Orders declaration that white clothing was heathen - did the Pruss in Teutonic service eschew their traditional whites and wear 'civilized' colors?