I have the same type window in my Trillium
4500 door, but have never removed it. I await the response as well. (In the absence of advice, I would do exactly as you described.)
I just finished removing, resealing and re-installing all the windows
in my Boler
1700. They have clamp rings similar to the clamp ring on the inside of the window in the Trillium
door, but no rivets on the outside of the window frame.