I'd say there are no more than 10 or so cart varieties found across the various aircraft types. I'm not quite sure what the numbers mean. The ones that say 'CA 777' are fairly common and not limited to the 777. There are some carts designed to hold bins of soda and other supplies, some carts meant to hold trays, some that have the heating element built in for economy meals, and some carts that are designed to hold a trash can.