There is now and GC patch for the RCM Version 1.3. You need it if you have compatibility problems with gc scripts from other mods. If you don't have such problems you won't need the patch. I updated the RCM full version 1.3 to 1.3.1 this new version includes the gc patch. So if you download the new version you won't need the patch as well.
Furthermore there is the integration pack with all features and fixes that came with v1.3 now available.