If your camper is a 72 model and your owners is a 1973. I am not sure which type of window you have? Is it the orginal owners manuel? The 1972 windows are different from the 1973 and 1975 models. My year (72) has a plastic inner pane that has it's own frame so we plan on cleanning it and putting it back. the 1973-1974 have an aluminum snap ring. From 1975-1984 have a glass inner pane and have no snap ring they are said to be the hardest. Check out the vintage airstream website and you will find more information in the FAQ section if you scroll through all the questions.
Juel, your year is different you have a totally different window . I think you might have to break the glass on yours. Check out the vintage airstrean website that is where I found my info it is in the FAQ section scroll through the questions until you find the question about these small windows.