Everything that's part of your Opus config and that actually matters (i.e. not things like the thumbnail cache, which can be re-generated and is huge) should be backed up, if you turn on all the options.
The config backup .OCB files can be renamed to .zip if you want to look inside them to check what they do and don't include and compare it to the /dopusdata /dopuslocaldata and /dopusglobaldata content. These two FAQs have some more details:
The manual also describes some of what is backed up by the different options: gpsoft.com.au/help/opus11/in ... rences.htm