Many parts are interchangable between GMC Envoy and Chevy Trailblazer… Vent glass is not one of them. The Envoy has a rounded corner on the bottom and the Trailblazer does not. Pictures follow.
Update: 1933trader on eBay made things right by sending me a new window so fast it almost made my head spin. This has been the best experience I’ve ever had with something going wrong with an eBay transaction.