Actual owner's or shop manuals were not available until 1964
. Prior to that, mimeographed copies of typed sheets came with the trailer pertaining to the various systems and appliances. Some of these can be found on airstream.net.
Also, if you'll look closely at your serial number, I believe you'll find that it starts with an "I" (letter) and not a "1" (number) for International model. The 28 is length in feet, the "0" is a zero for the model year, 117 is the number off the assembly line and the "T" is for the Twin bed arrangement. If you haven't found out yet, '59 and '60 models are the best, in my opinion. Of course I may be somewhat partial.