Find someone with access to the Scout accessories catalog. Someone on Binderplanet.com likely has one. A lot of the parts were aftermarket but licenced through IH to sell as dealer accessories.
I just went thru the catalog I have here from late 1979 and it does not have such an item.I’d have to get in touch with one of the main international harvester fanatics. I’ve spoke to, and contacted many, but no one that could answer that question yet. There were so many not in any book. Certain years you could get anything at all from the factory because sales were so low. They bent over backwards to sell scouts. That’s why there were far fewer produced than say broncos and Chrysler with the Jeep already had a big following from military guys. So, unfortunately, I’ll probably never get this question answered unless it’s already the answer I suspect, an unanswerable question.