Cat 2 plates used as CAT 3,a,b,c if airport runway used is approved and in force at time of approach,and if crew and aircraft are qualified.
Ie : Cat 2 shows 105RA,and you and your shiny aircraft are approved cat3a, 50 RA is set and 200RVR required.
Notams will tell you for preflight brief whether a cat3 is allowed.
If your a/c doesnt autoland on the centerline,always nice to advise ground about it and confirm it was your machine which
up rather than their system..
Safe Flights,