[Researcher]

Those appear to be a new set of barrels with the 1910 bolt plate. They have the V in a circle barrel steel mark. A set of Vulcan Steel barrels of 1899/1900 vintage would have the Kf barrel steel mark.

93358 03 Kf barrel steel mark.jpg

The V in a circle barrel steel mark generally begins appearing in the 135xxx serial number range about 1906.

Could you show us a picture of the left barrel flat and the legend on the top rib? may give us some more information.