How does your luggage find you if you give the porter at the pier your luggage and you don't know your room # until you check in? I booked a 'Guarantee' cabin for my sister-in-law...I have never booked one for myself, so I have always had my room# on my tags...
You "should" be able to get your assigned cabin number prior to embarkation day. If not, they'll have your name on a list and will assist in tagging your luggage with the assigned cabin number.