Configuring Reporting Services - ExecutionLogDaysKept Is it possible to set Reporting Services options when Reporting Services is not installed on a server?  Is this how a SQL Server instance used by SharePoint works?

I'm a new DBA (very junior...), and I'm working in an environment where the client uses SQL Server as a back-end to CRM, SharePoint, BizTalk, SCCM and SCOM.

I recently saw a user request to increase the retention period for Reporting Services logs on two servers. The RFC said to run Update ConfigurationInfo SET Value='275' Where NAME='ExecutionLogDaysKept' on DB ReportServer_BI on server [server_name] and DB ReportServer_RS01_Content server [server_name].

I had a look at both the servers but neither one had Reporting Services installed. At least there was no instance listed in SQL Server Management Studio.

When I ran the query SELECT * FROM ConfigurationInfo the results table returned had a row for ExecutionLogDaysKept.  SQL Server Management Studio was connected to the Database Engine when I ran the query.

I apologise if I've asked the question in the wrong forum.  Is there a more appropriate forum or website I should go to?
When you install SSRS 2012 in SharePoint Integrated Mode it does not install an instance of SSRS on the server like it would if you installed it normally.  So you have to configure it via the SharePoint interface. This is the reason you did not see Reporting Services running on the server.