Mostly. The logs contained in C:\Windows\Logs\CBS\ are diagnostic logs that can be used to repair your computer.
However, in general, the only log file you really should keep is the most recent one so the screenshot below shows you what a normal C:\Windows\Logsd\CBS folder should contain.
Earlier today however, we were working on a Windows Server 2008R2 and a 2012R2 server and found that both of them had about 40GB worth of CBS logs. That is not a good thing and so we deleted all of the CBS logs that were older than 1 month in age, which returned 39GB to drives free space.
If you are looking for other junk to delete as part of a drive clean up, you may find these two short articles useful: