I've taken out my Argosy fogged streetside curved window (I've been calling it the wing window, but I think that may be an Airstream term, judging by the posts I've been "searching" through).
It is plexiglass, and it is all shot.
It seems that the repair was done by removing the factory rivets on the top, bottom and right side of the frame. The rivets used to put the frame back on the body seem different from the factory rivets that were left in place in that:
1. Using the center punch to make a starter hole cleared the center stem right away with little effort,
2. Some of the rivets were showing a hollow center stem already,
3. The rivet heads could be popped off easily with a chisel because drilling them made them loose (if they already didn't spin in their holes),
4. The stems (after the head pops off) were loose in the hole.
I wonder what kind of rivets those were. I know that some on the body elsewhere where steel rivets because they were all rusted and were much harder to chisel the heads off of.
Plus the factory rivets are less bulbed out.
Hope the info helps. There's no learning like just doing it and taking the thing apart! Of course...putting it all back together, now that's an experience