AFAIK, an ILS system is an ILS system, whether the airfield is 'CAT I' or 'CAT III'.
The extras which make it usable with a DH<200' include, but aren't limited to, such things as lighting, local ATC LVPs, Standby power supplies, runway profiles and, of course, whether individual operators achieve CATII/III approval from the relevant authority for
each airfield.
The ILS bit is usually(!) the same wherever you go. (Or at least most places I've been i.e. Western Europe)