Every time we bring this topic up our English brothers start getting all defensive.....Why.
I mean if you read some of the web-sites concerning American long rifles (referred to as the Kentucky rifles to most people) there are some bitter fights over "This rifle was found in North Carolina and it looks like it was built there". "No it wasn't look at the patch box it was repaired in North Carolina but it was originally built in Allentown Pennsylvania".
The English shotgun and their makers are far better documented then our long rifles so we can investigate this subject with more documented proof as opposed to conjecture.
Plus, I could look at these pics of these high grade English sidelocks all day long!!!