The front 3 windows for a 69 Airstream, are still available.
However, the wing windows used in the 69 models are a real odd ball, as well as expensive. They also had a square outside lower corner.
Many owners added a small piece of sheetmetal to the shell, in that same corner, so that they could use the wing window that has 2 outside radius corners. That wing window costs about 1/3 the price of the 69 wing window.
As you face the front of the trailer, the 2 windows to the left and right of the center window are called wing windows. In 1969 only, the lower outside corners are square. From 1970 and up. that corner is round.
The other problem with all of the opening windows in the 1969 model year, used a crazy hinge. That hinge looks, at a glance, the same as trhe 1970 and up opening windows.
WRONG. If you install, a 1970 on up window, in a 1969 trailer, you MUST" change the hinge, using the hinge from the original 1969 window.
If you do not change the hinge, when you lower the 1970 and up opening window, every rivet that holds the hinge to the window sash, will shear off.
Therefore, changing the hinge, is a must.
Then the next problem, is you must use a buck rivet, that is smaller than the other buck rivets on the trailer shell. You cannot attach that hinge with pop rivets.
Airstream has been approached many times, about this issue, and some 40 years later, no solution has been offered, from them, except what I stated above.