That is a smashing photo, awsome...
I saw the Cessanas carrying the wepon back in the 70's, as far as I can remember the rocket pod[there was only one] hung from the left wing but I cannot swear to this.
There was a panel on the left wall of the cabin in front of the door,and the firing switch was on one side of the control colum, right hand I think.
I am sure I have seen a picture published of them firing.
They must have fired a few times ,as the pilots flying the various escorts/other missions would have to have been qualified on them.
They must have been stationed at Gormanstown too, as I remember seeing them there often in the late 70's , my impression is that they did not usually carry the wepon pod, it was put on as required.
If anyone knows what type of wepon was used,it could answer the recoiless question, is it possable that they were closed at the rear end??
Excuse me if this sounds a bit dumb.