Actually, that is not what it shows, anyone who has worked in a supply chain managed environment knows that you often do things in batches, if Apple takes that approach, they might spend 1/2 of a daily shift just building a specific model, maybe today they are building the 2.7/16/768GB models but yours will not be built until tomorrow. There are high levels of efficiency when building the same thing over and over, companies do it all of the time.
This is the reason that they provide a range, the only guarantee that they make you is that they will get it to you by the end of the shipping range. They know that within their schedule for the rMBP there are only a few combinations of what can really be ordered that has an effect on the internals ... 3 processors x 2 ram x 3 HD options ... there are 14 combinations (3*2*3)-(4 because the 2.6 and 2.7 do not have a 256GB HD).
With 14 options, and the fact that they provide a 7 day range, they could only build 2 different combinations each day.