Ian,
Basically yes - the micro-switch is just a very small version of a household light switch.
Orientation of the wires - which colour goes to which terminal - should not matter - unless there is a specific mention in the instructions that the +ve supply goes to a particular terminal. In which case, follow those instructions - and you will need a voltmeter to determine which wire has the 12V on it (probably the brown).
Take a note of the micro-switch "product code" - if you can see one - micro-switches have a life-expectancy of 100,000 operations (which should be more than the life of the caravan) but using them to switch an inductive load (pump) shortens this considerably. Then you can buy a replacement switch without buying a whole new tap.
Robert