Do I even need to add this list if I have the latest version of UBB?
7.7.5 changelog says:
Updated Robots (Crawlers) list from 20200114 to build 20200924
Source:
https://www.ubbcentral.com/changelog.php#775edit -
If it was an initial install of ubb.threads that you did, its included as the changelog says.
If this was just an upgrade you did, the robots.txt will be what came with your original version PLUS any customizations that you had done to it. ie;the content in this post is for you.