That is an interesting pattern found on some No. 1 guns and called "Bernard ribbon" or "Rubans Royal" (by Manufacture Liegeoise). Likely Hunter Arms got a deal on a barrel of tubes which were usually shipped from Liege as 50 pairs wired together (100 tubes).
1892 SN 22840. SNs 32146 and 35036 are recorded in the Hunter Arms Company Ledger No. 1 as Quality No. 1s and have similar barrels
1897 16g SN 60541
David Williamson's SN 42499. The Hunter Arms shipping records confirm No. 1.
and a 1902 F grade hammergun with the same pattern, I suspect the barrel guys were just using up Pattern Welded tubes at that point. Royal steel was introduced for the F grade hammergun in 1898.