In this case, there was nothing on the ATIS about CAT II or low vis procedures and we were never advised that this was in effect. But the preceding aircraft was cleared for a CAT II while we were cleared for an ILS approach.
If I understand correctly from the above posts, if the weather is a bit low such as at CAT I minimums, we are free to go ahead and use CAT II minimums but advise ATC about autolanding.