I don't know how they determine the sequence of production. When your smart is manufactured probably depends on several factors including which model you ordered (pure, passion, cab), the color(s) selected, options, and which port it is being shipped to.
In other words, I don't think they make them in the exact order as determined by the reservation number.
I spent many years in industrial manufacturing and most large volume manufacturer's run a similar product for a period of time to minimize re-tooling and changes in the assembly steps.
For example, they probably run a single model type for several days and then switch to the next model.
I am of course presuming that they have only one (1) assembly line. They may have several for all I know.
In any case, I doubt that they are making the cars in the same order as they were reserved.