I've never seen that colour combination before, but I have seen that technique used before with a silver evening sandal and a black midsole. This is the California glued method of shoe construction that was popular 1942ish to 1952ish. The sole is glued onto the midsole, after the rest of the shoe is already made by means of sewing the upper (in this case straps) to the midsole. This method of construction means you always have a visible midsole, which is fine for when you want a heavier looking sole, but it was great for wartime manufacturing because it could be made by semi-skilled shoemakers (ie: women with sewing machines) rather than skilled shoemakers who were employed in the production of sturdy army footwear.