Willy, If you want to make a close copy, then go to it.
As for the barrel swamp, I don't have any info on that gun, but a 1790/1800 Dickert that I know of has a barrel 1.020" at the breech, .940 at the waist, and .980 at the muzzle. About 45" long and 52 Cal.
Another Dickert barrel measures .980 at the breech, .920 at the waist, and .950 at the muzzle. About 44" long, and 56 Cal.
John