British black out serial numbers

[edNorth]

I need to sadden you. Of course the Germans knew, and made own efforts to conceal actual numbers, where made and so forth. Changes made to manufacturing plates are documented and are the reason for use of older ammunition codes for aircraft factories as well. Lots of estimates and references to Allied Production figures are found in BAMA files. But as "all" (plural) is known on them of no use to us, todays Historians (You know them that still do Research with captal R).
As researcher of both sides, I confirm.