devicergb_cs and devicecmyk_cs are no longer used and should be removed. They are currently now only referenced in gx_concrete_space_CIE. It is possible that there may be a few issues that need to be considered such as when the base space of the a DeviceN color space is CIE based. Need to look at how this is handled.
They are no longer used... except for in gx_concrete_space_CIE. I can't see where else we could get such colorspaces from for gx_concrete_space_CIE to return, short of creating them each time (and that seems like a bad idea). So absent there being some other place to stash them/retrieve them from, this seems as good a place as any to have them.