Question about 1929 Sterlingworth barrels

[Kirk Mckinney]

Gentlemen
I was wanting ask a question about the rib on my A.H. Fox 12 gauge. I was at the range the other day and picked up my gun from the rack with my fingers pressing on the top rib between the barrels and noticed that the rib down the center between the 2 barrels flexed in one place. I assumed that it was welded to both barrels solid. But after looking on the underside it seems there are about 3 or 4 round pins that are flush with the bottom rib. My question is are the top ribs pinned to the barrels?? If they are then I could understand it flexing between the pins. Not sure if this is something to be concerned with or not. Thanks in advance for any insight you might have on this matter.

See you in the field.