Yes, wings down would be correct. An original would be next to impossible to locate. They are not repro'd to the best of my knowledge. Only a few thousand cars were made with them, so it's probably not very high on the list of things to make. Ames carries the "wings up" style.

However...a clever individual could use clear acrylic resin and one of those nice mylar decals to make a passable facsimile.