From top to bottom:
M/49 Marinepistole - The first German navy pistol, 1,000 purchased for the First Fleet, the Reichsflotte created in 1848.
Marinerevolver a/m (Colt 1851 Navy, no official Model designation) - 3,000 confiscated from Colt in 1855, 1,000 issued to the Prussian Navy in 1858. Shown with it's holster (top right).
M/69 Marinerevolver - 500 purchased in 1869 and 1870. Shown with its holster (lower right).
M/79 Marinerevolver - an estimated 2,200 Reichsrevolvers were procured by the Navy. Shown with its holster (left).
The M/49 was carried by a belt hook, so there was no holster. Note that the other holsters all include a pouch to carry a box of ammunition.