1971 Duster Twister Rallye Wheels without Center Emblem?

I've personally nerver seen a ralley wheel without a center cap. Someone please correct me, but my library says all 1970 ralley's had light Argent center caps, and 1971's all had dark Argent center caps. Trim rings only came on 70-71 340 cars. If I'm wrong, please correct me.