Howie, from what I remember the exit window on the 345s is the same window (rectangular) that is used on the trailers so I would think your instructions would be spot on.
I wonder if Airstream sells the complete hinged window section only, i.e. the part that hinges out in lieu buying the entire window assembly?
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)