So between zero and never, what are the chances Claremont ever comes back to explain the events of the 6 month gap before Revolution?
The costume is a product of it's time, when colors had to bright and draw attention be it for villain or hero, sour or happy characters.
To draw attention to it would mean to draw attention to the sliding time scale. So it's generaly advisable for writers and readers alike to just roll with it and write it off as grandfather clause, instead of trying to explain it in story and make it fit into modern sensibility or trends, which will then just make it even more arkward.