Hi Rich,
For those of us that like the details and because there is little or no data from the Mauser Factory (they were destroyed) we had to improvise.
If you collect enough data from your friends, gun shows and books, you then know the approximate beginning and ending serial numbers. From these serial numbers, one can estimate the number of Lugers produced for a given year and also any sub-variation. Then I assume a uniform production schedule and determine the month the pistol was produced.
Lots of work to accumulate the data, but worthwhile.