I believe that your previous impression is correct. There is no listing in the '34 body parts catalog for sun visors for a cabriolet nor do they appear among the ten or so Ford archives photos that I have of '33 and '34 cabriolets. I've had one of each and neither had provision for mounting sun visors. Perhaps the book reference is a proof reading error because they are not mentioned on page 113 where the specifics of the cabriolet trim schemes are listed, unlike comparable listings for other body types with sun visors elsewhere in the book.
The book is a great resource and we owe George DeAngelis and Ed Francis (may they both rest in peace) our gratitude for sharing its contents with us. That said, like nearly all such writings, some errors are made and not always caught in the proof reading process unless the proof reader knows the topic at least as well, if not better, than the author(s).
