1971 Duster Twister Rallye Wheels without Center Emblem?

The only place that I have seen a factory Rallye wheel without a center cap in factory literature is in the 1970 Dart factory brochure in the list of options. This was the first year for those wheels and I think that they just didn't have the center caps ready when they put the brochure together. All the cars in the brochure have either full wheel covers or poverty caps.