If you're dealing with a version of SQL Server greater than SQL Server 2000, at this point I'm going to say yes. The reason I say yes is looking at the files that are updated. For instance:
- SQL Server 2005 SP4 GDR file list
- SQL Server 2005 SP4 QFE file list
- SQL Server 2008 SP3 GDR file list
- SQL Server 2008 SP3 QFE file list
- SQL Server 2008R2 SP1 GDR file list
- SQL Server 2008R2 SP1 QFE file list
- SQL Server 2012 GDR file list
- SQL Server 2012 QFE file list
What is clear is that it's more than just SSRS specific files being updated. Therefore, it looks like it is best to patch all installs of SQL Server 2005-2012. SQL Server 2000 Reporting Services was a stand alone component, so I don't believe this should affect anything other than specifically SQL Server 2000 Reporting Services.