Most if not all the 24hr 'A-11' Elgins are actually recased gun camera watches. Elgin made versions of the 647, 685, and a variety of their 13/0 movements for this purpose. I recently acquired one of these - the movement and dial only. It's a real, 24hr, hack-setting movement, but it wasn't built for wrist wear. I bought a Star A-11 case for it, which I believe it will fit, but I'm keepin' it!
I see you also hit the MWR forum, so I won't tell you to go look there! From what I've read there, I think most folks believe that there were no 24hr A-11's issued, so they ALL are either Frankens or recased camera watches. I do happen to own a 24hr Elgin from around 1960, though, that has a dial that is definitely not military - white with raised gold numerals - and it's in a gold filled case with 'Cased and Timed by Elgin Nat'l Watch Co'. stamped inside the caseback.
I see you also hit the MWR forum, so I won't tell you to go look there! From what I've read there, I think most folks believe that there were no 24hr A-11's issued, so they ALL are either Frankens or recased camera watches. I do happen to own a 24hr Elgin from around 1960, though, that has a dial that is definitely not military - white with raised gold numerals - and it's in a gold filled case with 'Cased and Timed by Elgin Nat'l Watch Co'. stamped inside the caseback.