In general, LEGO advent calendars are boxes where for each day, there is a small model, or sometimes a minifig, hidden behind the window. Some superficial instructions on how to assemble the model are printed on the inside of the window lid.
Now, in general, the exact content of an advent calendar is supposed to be somewhat of a surprise to the one opening the window. While for LEGO advent calendars, all minifigs and models are contained somewhere on the imagery that decorates the outside of the calendar, I wonder whether at least the ordering is a bit of a surprise.
Or, in other words: If I bought the same LEGO advent calendar twice, would there be a chance that the content were ordered differently? (The box art on the 2019 city calendar weakly implies the answer might be yes, given that the example on the back side shows some open windows with their content, and said content was due on different days in our own copy.)
Thus: Are there differently ordered versions of these advent calendars? Are they somehow randomized, or is there just a handful of different sorting patterns? Even if so, are there any windows/days that always have the same content (e.g. day 24)?