Ken,
The in-flight Fortresses with the triangle L were from the 381st Bomb Group. We were fortunate to meet Bob Armstrong a few years ago, and he was flying one of those Forts when the photos were taken. I think it was aircraft "D" in the background of the first two shots. He wrote an interesting book that is a compilation of his wartime diary entries. The title is "Friendly and Enemy Skies" and is a great insight into the life of combat crews in England.
You're correct about the Squadron "B-17 In Action" book and Little Miss Mischief. There is a photo of the damaged original waist area and a line drawing of the final product after repair. Here is the side view from the ancient Microscale decal sheet:
Scott