At The airline for which I am a trainer, and have worked on both Boeing 737 and Airbus. CAT III training is covered on the conversion course and a pilot is not allowed to complete his/her final line check until fully CAT III current.. .. .The only time a pilot could be out of check for Low Vis Ops,is if for unforseen circumstances it could not be covered on a recurrent check. This is very unusual and the person concerned is usually revalidated within 28 days.. .. .Is someone cutting corners here to save cost.. .. .Also, never admit to the passengers that you are under training. Unable to land due to the poor visibility covers it just fine.