They were originally held on with "glass setting tape". I know DMT sells the correct thickness tape for the front wing windows. I bought some but haven't tried using it yet. The videos I've seen on Youtube don't give me much confidence in trying it myself. I think some people use windshield urethane.
Agreed, setting tape was the OEM method, myself I've used windshield urethane to remount glass channels, takes longer to set up/cure, but IMHO the results are much better in fit/finish.....
No glass setting tape on a 66-70 B body window, or A bodies either. The bracket is NOT bonded to the glass on these cars. The lower bracket is attached with a plastic rivit. The bracket has a gasket paper between the glass and bracket. You can make the paper gasket yourself.
The door glass is easiest to replace with the vent window assembly out, and drop the whole assembly, side glass and vent assembly down in one unit.
Now is the time to wed the lower stud bracket back on, if it's broken off, which they almost always are.
Don't over look the front "fuzzy" strip too. The repros are hit and miss for fit. Buy a new OEM mopar strip set, but be prepared to pay $$ for them.
FYI, the new white clips are oversized, so reuse the originals if possible.
The AMD glass fits well. I have used plenty on customers cars, and my own.
Other repro door glass brands tend to have the wrong curvature, wrong size hole for the plastic rivit, wrong thickness of glass, which all make it virually unusable.
Here's one source for the rivit. Highly recommend this company and it's excellent products
https://www.detroitmuscletechnologi...ss-window-regulator-plastic-nylon-rivet/ 
