Like I said... I have never seen one with the "twin strut" mirror. But sure, it makes sense they were an option. I have noticed that 67 Barracudas tended to be a little "up optioned" compared to Darts and Valiants — Plymouth thought of them as "premium" and the dealer cars were seldom baseline models. But anyway, they do seem to have a different shaped base, which was the question (although those accessory illustrations are not very accurate — I guess that catalog was put together using the stylist's concept art, before they had any production models to photograph).
