Exactly. Malkie and kevinpdx are of course right about the guesswork that is involved with pre-modern figures, but, as an example, there are plenty of tomb effigies of high/late medieval regents and knights so we know more or less exactly what their armour looked like, can imagine the colourful splendour in which they appeared in the field and yet Hollywood, Netflix etc. and even "educational" documentaries choose to portray these people in drab rags and gear that's either 200 years out of date or entirely from fantasy LARP even though more authentic replicas are readily available.I think that if the figures being sold is of an actual person it is important that it is historically accurate, there is no excuse for putting somebody in the wrong uniform. Having said that, i do accept that sometimes paintings of the period may be in accurate so perhaps that could be the cause. But, the point is, I think that a producer has a responsibility to ensure it is as accurate as possible.
That's why I can forgive small flaws, as long as the figure as a whole is plausible.