Letter received today.
By reading this letter, does it appear that this shotgun has two sets of barrels or three? To me it looks like three, unless I have misread it. I have the Bernard set choked mod. and full, with a "2" on the forend lug and "2" stamped on the forend itself ahead of the serial number.
I googled SD&G and got nothing as far as any surviving record from them. I googled "J.E. Lawson Columbia SC census 1900" and got the runaround as far as links. Nothing definitive on Mr. Lawson yet, unless someone can suggest a better website.
This is the fun part about these guns, researching past owners, their histories, occupations, etc. Thanks to all who have helped so far.