Fiebig, Unsterbliche Treue, Berlin 1936 p. 59, says that under Friedrich Wilhelm I, the poles of the cuirassier standards were usually painted in the colour of the cloth of the standard, but "kanneliert" (painted with perpendicular stripes) in the coulour of the embroidery. According to Fiebig, this was not changed before 1806 (I haven't checked for the later period).