Greetings Shame!
Welcome to the Forums and the world of Vintage Argosys!
I suspect that your Argosy's air conditioner is an Armstrong, and as was posted by Argosy 7728, Inland RV is probably the best source for a new replacement shroud. When compared to other RVs the age of our first generation Argosys, there are many parts still available from the manufacturer . . . and there is a remarkable number of reproduction parts available from a number of vendors who are active here on this Forum.
- Vintage Friendly Airstream Dealers
Inland RV -- Corona, CA
Ace Fogdall RV -- Cedar Falls, IA
Out of Doors Mart -- Colfax, NC
Vintage Friendly Parts VendorsVintage Trailer Supply -- Vermont
Fantastic Vent -- Elkhart, IN
Zip Dee, Inc. -- Elk Grove Village, IL
There are many other, but the above are a sampling of sources of parts for our Vintage Airstream and Argosy travel trailers.
Something that you might want to consider before towing your Argosy a significant amount is the addition of a rock guard to protect those valuable clear Panoramic front windows . . . the deep wrap wing windows are now available only in Solar Gray tinted rather than the clear utilized on our Argosy travel trailers . . . and the cost of a new deep-wrap wing window it typically in excess of $750.
I am sure that your Argosy will provide you with much enjoyment as you learn more about its unique character!
Again, Welcome to the Forums and the world of Vintage Argosy ownership!
Kevin