You only need to copy the *PGM objects.
You do not need the source or *MODULE as these were only needed for the object creation.
Many thanks Charlie.
You need to copy *PGM objects if you updated modules in programs. But you need to copy *SRVPGM objects if you updated modules in service programs.
The *MODULE objects would only be useful for developing programs and service programs. They probably will never need to be copied to another system. The *PGM and *SRVPGM objects contain executable code and whichever ones are changed must be copied over.