I attach an exploded view. That 'Drum Weight' was certainly used on Models 450407 and 450431. The 17" machine appears to have never used it. The weight was attached to the RH side roller.
My parts manual says: Drum Weight to Mach. No. 450995 the p/n was 453384 Drum Weight from Mach. No. 4504996 the p/n was 451590
Given that the part number changed (with the screws holding it), I am guessing the weight was adjusted too - for unknown reasons.
Hope this helps. --------------------------------- Jack
