There is no phraseology difference for a Cat 2/3. You receive a normal approach clearance; it is up to the crew to review approach charts, notams, opspecs, aircraft MEL’s, etc to determine the appropriate approach minimums. Normally US/FAA ATC will automatically protect the ILS critical areas when weather conditions are less than 800 foot ceilings or 2 miles visibility, but it is up to the crew to advise ATC that an auto land is being conducted and to request they protect the critical area, if they are conducting one, especially in weather better than previously described.
https://www.faa.gov/other_visit/avia.../SAFO21004.pdf