I have emailed you the following:
Yes, you need the banana wraps. Here is a link to a dealer locater:
There may be one near you. This is a do it yourself project. You will need to probably plan on replacing the rubber insert as well - it has to come out to expose the upper rivets and may not survive the operation. This, too, is available from the dealer.
I suspect you will find only the Airstream banana wraps are still available, and they are a dark brown. I thought the Argosy ones were, too, but if they are in fact black you can paint them.
If a local dealer seems uncooperative or ignorant, you can order from Airstream direct, or one of the dealers around the country that mail order. Andy at Inland RV is an active participant on this forum and has forgotten more than the rest of us will ever know.
Since this is an exterior project, you will need Olympic rivets, in my opinion. Some may argue that with the upper rivets hidden behind the rubber trim, and the lower ones being upside down, regular aluminum pop rivets will work.