Hello I just acquired this Benjamin 312 and would like to know the date it was manufactured. It does not have a serial number so I know it’s pre ‘57. The bolt handle is able to unscrew and is straight instead of contouring with the barrel. It says “St. Louis Missouri” on the barrel. There’s also felt inside the “tootsie roll” that I assume is not stock? I have attached photos. Any information is greatly appreciated. 
