I have seen more Longrange 3" chambered guns with the re-enforced lug than the Wildfowl guns. The two Longrange I had, both had the re-enforced loop. I also have a Trap Grade c. 1927 that has an extra set of barrels and both have the re-enforced loop. All have splinter for-ends.
Some of the very early Fulton guns had a flat piece of metal that was between the loop and barrel block. These were usually soldered to the loop and had a screw near the block and I'm guessing to let water out when the barrels were rusted and or etched. I think this was just a cosmetic piece and not a re-enforcing one as it is only about 3/32" in thickness.