Thanks guys for all the responses. As Rick alluded to, the only three 26" barrels in the spreadsheet all have one line addresses. I like the theory that the one liners were the earliest barrels because that would make mine "correct" for my 1919 Model .250-3000. Obviously that's going to be hard to prove though without more info.
With respect to Rick's comment about the two lines being separate dies, I believe that is correct. On my rifle, as close as I can measure, both lines are the same length (2 3/4 inches), but the patent date line is offset about half a letter to the left of the address line. If they were struck with the same die I'm sure they would line up exactly.
