I searched the forum and I read there is a L shaped window stop that can be removed to lower the window down further to remove window felts. I couldn’t find that, I did find rubber bump stop in the roller channels, is that what I need to remove? Any help would be appreciated, thank you.

 

Which body style? The window mechanisms are different. And you should be searching the Fisher Body Manual, which has illustrations of the window mechanism parts for all body styles.