Originally Posted by Markeyro
Do you remember the shape/size? Also would you know anything about the door gasket / seal?
The one that I used on my 1980 Caravelle (which has a lot in common with the Argosys) is the following D gasket with part number 45370. I found it at Inland RV.
Inland RV Center Inc.
Part #: 45370
I would speak directly with the people at Inland RV since they know how much you should buy and everything. Measure the size of the window and they tell you how much to get. On my Caravelle, the window gasket and the door gasket are the same thing so I just bought one long piece and cut it to size. Make sure you get the adhesive as well. I used 3M weatherstrip adhesive. Here is a link although probably not the best price: 3M Super Weatherstrip Adhesive - Adhesives - 2KVC4|8008 - Grainger Industrial Supply
Good luck and wear gloves when you apply the adhesive since it is possible to get your fingers stuck together and that stuff is a pain to get off
I remember following a thread on this forum that outlined the process well when I did the gaskets on my windows but I can't remember where. You should be able to find it with a quick search.