Unless the barrel tubes were made with above average wall thickness, you probably don't want to have those barrels rebored; could make the barrel walls too thin to shoot the gun safely. Barrel pitting is indeed very unsightly, but most barrel pitting is not so deep that it will impact safely. My suggestion would be to have those barrels inspected by a qualified double gunsmith; and if then judged to be sound, use the gun with shells loaded to period pressures. The chambers on your Baker could be shorter that today's 2 3/4" standard; so, if that's the case, I suggest you use period shells of the proper length, or open the chambers to 2 2/4" (most American double guns have ample thickness in the chamber area for legthening).
