Early American skeet sxs often had the R barrel choked tighter than the L, for doubles: "Skeet Out" R, "Skeet In" L. Not likely the case on this gun, however, since it's British.
Driven birds . . . I have an old auction catalog from Christie's, back when they were in the gun business. The catalog features several pairs of guns. Although it seems to be a popular belief that guns were choked tighter R barrel and more open L for driven birds, NONE of the pairs shown in the catalog are choked that way. And British pairs in particular were usually purpose built for driven birds.
