Bob,
Yes, if the chamber size is marked on the barrels and it was indeed made in 1926 as per the serial number, then sometime in it's life Savage had the gun at their factory and decided they would stamp the chamber length on the side.......sad, but that's what they did to any of the "Philadelphia built guns" that 'visited' Savage for any work. Savage took it upon themselves to 'lengthen' the chambers and stamp the barrels, interesting story for sure.
Somewhere I read that they did not tell the owners about the additional marking either, so many were unhappy when they got their guns back, or so the story goes.
Best,
