I sort of understand/get what you mean...
The automatic wipe of the rear window when you select reverse is
about the only thing that was standard fitment across the
entire ForFour range of models. It is not an option or a mod.
There was a massive list of parts/bits/items available as options that
were either fitted at the factory, or a dealer fit option, or available to
buy and fit later. The higher specification of the model you ordered
(Pure, Pulse, Passion, or Brabus) the less options that were available
or became available as they were standard fit for that particular model.
So each ForFour can and will be a bit different to another.