Hi Umi.......
The gun house shown below in image WP20150218 is an Oto Melara 76 mm with shape being spherical or dome like from the top
However the mounting shown in 21.JPG is clearly an alternate format
The Oto Melara 76 mm was acknowledged as a brilliant design and as used by a dozens [60?] of the worlds navies
Two of my colleagues lost fingers
from their right hand when adjusting the recuperators within the mount on our HMA........FFG's
I did not like the maintenance procedures
on these gun mounts.......
It was common to install the Oto 76mm mount on
largish patrol type craft..................Derek