I have found many "solutions" for this problem, including modifying gsettings.py, as well as installing Gnome Tweak Tool or Unity Tweak Tool. I have even attempted using Gnome 3.10. Nothing I have tried has worked.
The issue that I am experiencing is that, within Gnome Classic, I am unable to change the window borders. Most GTK3 themes installed in ~/.themes/ work in the sense that I am able to change the GTK theme, but not the window borders (Border, Title bar, Close/Maximize/Minimize buttons)
I was finally able to get Window Borders using the correct theme while using Gnome Fallback, however, Gnome Fallback does not seem to be an ideal solution for me (introduces many more issues, such as Keyboard Settings not having an affect on my session).
Does anybody have any suggestions on how to get a Gnome Classic session honoring both GTK and Window Borders of a theme?