Good comment, but I couldn't help notice that you got the date (6/6/1944 != 6/4/1943) wrong for Operation Neptune/Overlord: https://en.wikipedia.org/wiki/Operation_Overlord
And I did mean Neptune, the Overlord plans would have remained valuable for several weeks as they included details of the immediate objectives in Normandy and how resupply would be done, Neptune was just the invasion and related actions.