For the rectangular ones on the 73/74's Harbor Freight has a rectangular boat LED that works very well, and what I put on mine. Not being a purist, I used the same light on my 75 rear door 22' in place of the square ones it had. I had to cut some plastic on the newer one, and on the older one, mounted the lights on a piece of metal which was then cut to the shape of the original light opening, and then screwed in place with SS screws.
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.