The original stainless trim had little brads (nails) welded to the back side. Once the rubber and window was installed, you would press the brads into the rubber molding. However, most of those brads rust away or break off, so I would suggest using an adhesive, like caulk or something to hold the stainless on.
The window rubber is an āSā shape (cross section) I believe. Make sure you have the right rubber and the windows should go in fine. Sometimes it takes a try or two. Use windex glass cleaner or soap during installation. Makes it easier.
This is a great video for glass installation...
https://youtu.be/blaD0vgEUDU