Yes. I have since deleted both GP-Premium and the theme and removed all child themes from the site.
Full disclosure: I imported six json settings from my test site during the first install.
A fresh reinstall still yields the same – the only thing that appears in the “You Are Customizing” dropdown is the text “The Customizer allows you to preview changes to your site before publishing them. You can also navigate to different pages on your site to preview them.”