MSS is Rel4 concept, meaning there is no switching part in it, all switching and termi*na*tion equipment is moved to MGW (media gateway).
MSC includes switching part e.g group switch.
Correct Kuna. 3GPP Release 4 was the specification that was used to introduce
MGw and the re-purposing of the MSC as a pure signalling node. BICC (ISUP and CS-2) was also introduced.