In the registry look under HKLM>Software>KVS>Discovery Accelerator>Install
There will be a version key. The RG version should match one of the follwoing
5.018321 May 2004
5.0 CP1a2069 Jul 2004
5.0 SP221531 Aug 2004
5.0 SP32354 July 2005
5.0 SP424120 Dec 2005