The Kronoskaf article - based on an original article by Jean Vial - is correct : les rouges and les bleus referred to the colour of the artillerymen's smalllclothes, not that of their gun carriages, which were all blue at the time regardless of whether they were the Vallière or the Gribeauval type. Blue smallclothes were introduced by the same 1765 ordinance which intended to replace the old guns with the new Gribeauval ordnance
None of this is relevant to the SYW however since Gribeauval's changes did not occur until after the end of the war, so Rafa's colour scheme is entirely correct for the 1756-1763 period.