Here are links to the Airstream companies book store, where you can purchase the Owners Manual:
And the Service Manual:
For each just select the year (1972) and order them! These will be very valuable to you in operating your trailer and will be especially helpful if you need to do any repairs. These manuals also come up on ebay every once in a while, but Airstream has them now, so why wait?
Best of luck. If you need pictures of anything, please let me know and I can go out and take some. My trailer is just behind my house, so it is very easy for me to check on anything that you may have a question about.