As I said its been quite a while since I worked on the ramp at NCL, but I don't think the interview will be too testing. As with most things, appear keen and interested in the industry and you should do ok.
When I was interviewed originally they were far more concerned with how I would cope with 4am starts and 3am finishes, and how prepared I was to do overtime, learn to drive strange equipment than anything else.
Might also be worth trying to at least have a note of what airlines the company handles, and what sort of aircraft you'll be dealing with.
Good Luck
RTG!