Hi gents,
The Hawaiian Air Depot (HAD) had several mods to B-24Ds, with each variation keyed to the user air force (Fifth, Seventh, or Thirteenth). I've passed all my documents to another researcher, but the tail turrets could be removed to save weight and/or provide a nose turret for the same or another aircraft. Much of this is in Alan Griffith's Consolidated Mess, and I expect more details in his upcoming glass-nosed Liberator book.
Cheers,
Dana