Here is a bit of information that may help you pin down the date of change. I have a 1922M1 Springfield that was shipped from Springfield Armory to G & H in April 1934. It must have been one of their more basic custom jobs as they used the NRA stock the rifle came in. It does have the barrel band mounted upper sling swivel. It and the rear sling swivel bases are the wide type like are found on the old super grade Winchester Model 70. FWIW