Hello Tony,
Your member info says you have a 1976 AS, it lists you as a new member, and says your join date is 2010?? So, adding to the confusion, are you fixing a specific year AS or building a tiny house or parade float??
I ask because the Philips-Corning windows are somewhat year specific. A '66 window has an "un-serviceable" glass-bar, they're a bit of a hassle when replacing glass. '67/' 68 glass-bars are similar to each other, in that they can be removed from the frame/jamb, not exactly the same, but perhaps interchangeable with eachother. The 1969 window does not have any similarities to the Corning-Philips. That's not to say that a 1969 AS could never have been built with a '68 back window, because AS is known to use up old inventory during model/year transition. The 1969 back window is not a replacement for the "Philips-Corning".
Asking for a window frame specific to the year, would be the best first choice if you are wanting it to match all the other windows, if that is your quest.
Not knowing your plan, Sorry if this is totally irrelevant to your project, but if you're looking to repair a
1967, for example, a
1967 jamb/frame is most appropriate and least hassle. A
1968 would be as good, a
1966 would work, but with difficult glass replacement. A 1969 wouldn't match, but the 1969 does have a non-Philips-Corning, only 1969, square corner back window, whose dimensions I don't know. It might cobble in tho...
Good luck, I know the bone yards are pretty picked over, and those windows are not cheap.