Hi Ez, 42 byf, serial number 2070i was completed about June 1942.
It is thought the German Military Contract ended either just before or in the early M-Block. Mauser continued making "42 byf Lugers" for the Portuguese about 5000 in the M-Block, then another 6000 or so, maybe 6500 for Bulgaria, ending in the N-Block.
Hope this helps!