What do the dates next to the revelations in the Tadhkira mean?
They show when each revelation was received, as precisely as the available evidence allows. Sometimes the date is certain, sometimes only very probable, and sometimes only the year is known.
The Tadhkira is a collection of the revelations of the Promised Messiah (as). It arranges them according to the time at which he received them. The notes beside the revelations therefore state when each revelation came.
The exact day has not always been recorded. Where the evidence is clear, the date is certain. Where it only points to a period, there may be just the year, or a time between two months. The note then means that, as far as is known, the revelation most probably came at that time.
Such notes help understanding. A revelation is often connected with what was happening at its time. Knowing when it came makes its context easier to see. The Holy Qur’an, too, was not sent down all at once but piece by piece, as the verses above say. Every revelation has its place in time.
Numbers that stand inside a revelation are a different matter. They are part of the text, and each has its own meaning. There is no general answer for them. One has to look closely at the particular revelation to say what a number in it means.