The reason is that in the M43 regulations, and up until M1958, gold boards are actually service boards which are also used for parade and olive boards are field.
In 1958 the service board become olive and gold is only for parade.
Was there a design change in the propellar above the star on the shoulderboards? The one on your pic (sovvisor) looks different from the one in the pic far up in the thread.
