Your assumption is incorrect.
First, make sure you selected "Topo" or "DCT flow" or something like that as an option to the RM-script downloader on SolvNet.
(I don't recall if Topo flow is in the default config for the RM script for DC)
Second, look at file rm_setup/dc_setup.tcl, and search for where the mw_reference_library variable is set.
Notice that the RM script sets this from another variable MW_REFERENCE_LIB_DIRS, which was set earlier in common_setup.tcl.
The key hint here is that this is only creating a list of MW *DIRS*, and not a list of files.
MW libs typically can contain e.g. CEL and FRAM views, and DC already knows implicitly to look under a FRAM/ subdir under the directory paths that you list here.
(if you do not already have FRAM views of your tech libraries, then you are not even ready to do this step and need to talk to your library vendor)
Bottom-line is that you are making a list pointing to all the root-dirs of your various MW libs (std-cells, I/Os, RAMs, etc.), and not to individual files nor to the FRAM sub-dir.
The commands needing this list of directory paths is create_mw_lib and set_mw_lib_reference, which should be obvious from the RM script content.
Finally, note I have not looked at RM-scripts since about v2011, but I doubt any of these details have changed since.