Well, that honkin' long one looks to me like a Smith & Wesson Model 24 .44 mag, and the bottom one is a Colt New Service DA, either .45 or .455 Eley, minus the ejector rod under the barrel methinks...
1941. German (Air Force) Model L double barrelled signal pistol. sometime also called Fl ("Flieger-Leuchtpistole L" = Aviators Flare Gun L). The L is made of aluminium and first produced by Emil Eckoldt in Suhl. Frame stamped Fl 24483 and has a makers mark GBW on a triangle. It has a brass lever at the rear to select the left or right barrel and there is a safety catch on the left. A lever at the front of the trigger guard opens the breech. The grips are two piece dark brown checkered plastic held together with a central screw. This type of signal pistol was made for the German Luftwaffe and collected at Tobruk by the Australian Military History Team.
Bumping this because I'm planning to make a replica of the bang gun. I'm thinking the bang gun is the same model as the Colt New Service that Jack uses throughout the film, but I wasn't sure if that was confirmed?
For reference, here is a Colt New Service:
The gun that Batman kicks out of Jack's hand at Axis Chemicals:
The gun Jack uses to kill Bruce's parents:
And the Bang gun (just tough to tell because of the lighting)