As originally built, the Irex shears were probably very similar to this photo to the right of the Sirago. The Irex had a 5"/25 deck gun on the after deck and two smaller 40 mm. cannon, one on a "“chin mount” below the bridge and the other on the aft “cigarette deck” The boat was originally described as having two 40 mm. canons, but at some early point this after cannon was removed.
Below are two photographs from the Finch collection.
Here is a picture of the 5"/25 aft deck gun.
The above photo shows the 40mm cannon mounted on what came to be known as the “cigarette deck”.