It wasn't uncommon, as it isn't today, for an inventor to patent his or her idea before selling it to someone else. Unless the employee develops the patent on company time, that's usually the case, so should that de a registered design trigger, the fact that it wasn't assigned to SAC from the beginning will be less relevant than IF that patent was applied for before the end of SAC production. Let's not forget where and when we are discussing, Syracuse NY. Syracuse was perhaps the most important city in the US it terms of SxS production and evolution. Many makers and inventors were not only within the city limits but were located in the surrounding region...Ilion, Fulton, Rome...with guys like Alexander Brown, Hollenbeck, Horne, Lewis, Thorneley, and Dan Lefever kicking around...not to mention Hurst, Roy, Giddings, Charles Green, Charles Lefever and Rosenburg ...and surely these guys talked about the successes and foibles of their Syracuse predesessors Andrew Whitmore, Fay, H A Castle, Louis Diss, and L L Hepburn...and I'm not naming all of them, just a few important minds in the region...and Ithaca was just a barge hop away..
Reb says that there appears to be no filler strips in the trigger strap. Could you please double check it with magnification.