Daryl,
I see what you mean. I examined my conversion guns, 1 Dangerfield and Lefever and 2 Barber and Lefevers. There are residual, although worn proof marks on the barrels in the flattened areas. Apparently the proof marks were deep enough so that they did not disappear with the filing to create the flat part of the barrels to mate with the soldered lug portion of the flats.


Great-Great Grandson of D.M. Lefever
www.lefevercollectors.com