[Pharo-users] How does Metacello check for installed packages in the image?

Hi, I have a Pharo 6.1 image with packages loaded manually (without BaselineOf or ConfigurationOf). Now if I evaluate a Metacello script which would install the package already installed in the image (for example via dependency), is there any check performed against the RPackages or similar to avoid loading it again? Cheers, Hernán