The Royal Black Watch Regiment have an insignia that is similar to, but not the same as the insignia for the current real life Black Watch, the 3rd Battalion, Royal Scots Regiment. Other than that exceptional unit, they don't have unit insignia attached to them other than maybe the Cameron Star. If the Royal Black Watch are any indication, they likely did continue using an evolution of the current real life unit insignia, unless the Royal Black Watch were the only unit allowed to keep their traditional insignia.