I have used Still's Third Reich Lugers as a reference. The production of Lugers ceased in November of 1942. The German Military Contract spanned the suffix range from no suffix to just into the M-Block, thus 12 Blocks of 10,000 (I'm not counting the M-Block). Add another 10,000 for the Portuguese and Bulgarian Contracts (M-Block, just into the N-Block) and that makes a total of 130,000 Lugers (Still claims 123,000 - don't forget the byf 41 Lugers in the ns, a and b Blocks). It is unclear if the entire production of Lugers ceased in November, or just the German Military, since Lugers and Luger parts manufacture continued until late 1944.
If we count only the German Contract completed in October, then the pistol (599k) came off the assembly line about mid September. If we count all the byf 42 contracts being completed in October, then the pistol was finished in the first third of August.
Now having said all this, I have based my calculations on an average number produced every month, which is probably not correct. I feel that the calculated production date is only approximate and to pin it down to a certain day or even part of a month is really stretching the statistics. That is, unless one has a much better crystal ball than I have.