Jake, Two of my Ithacas have 26" bbls, and both seem to be original. One is a 12 ga Flues with 0 and 2 chokes, Cyl and mod. The other is a late NID 20 ga with 1 and 2 chokes, IC and mod. I have no way to measure the choke length on them, but both touch at the muzzle and look original to me.
Curtis