Ah, I did actually download the latest gcc and installed from source. An older version which has .so files up to .so.5 came with the distro i.e. /usr/lib/, but the .so.6 file is in /usr/local/lib, presumably from when I installed the latest gcc.
Is there no way I can tell rpm that its there? Are there any rpms for gcc (I found some but they were either old versions or for x86_64, etc)?