View locked theme options

I’m working on a new book and I’d like to apply the same theme options (and custom css) that I used in a previous book. Only I locked the theme on the existing book when it was published.

Now I can’t even view (to copy/export) the options or custom css that I created for that book, and of course if I unlock the theme to solve the issue, I open up the possibility that the existing book is affected by theme updates that have happened since that was published.

Is there any way to view all the options and custom css code applied to a book with a locked theme (so that I can duplicate them as the starting point for a new book)?