It should come out with the window. I haven't done mine. But have done opera windows. Which are different to do. Have done earlier GM cars
If GM has stayed the same, remove inner moldings,
Which should expose a rubber ridge. Use 2 screw drivers.
And cafefully undo the rubber from the body lip.
Ask a glass shop first though.
Some where I remember GM changing the way they put large glass in... But no special tools are needed if the first way.
If that's what you have. .............................
HTH'ed......You can remove inner molding and discribe what you
Have and E-me..If that helps.....Good luck
Might want to check the forums,sure it's been dealt with.