Try Steve Blancard here on the Barn he goes by ndnchf OR where it me I would send HIM your generator and let him rebuild it for you....NONE better than him and his work!!!! He is "TOP NOTCH". It will be better than when it was new and 100% concours. You can youtube his videos he had done on a few generators and his quality of work and upgraded bearings as well as he has posted both pictures and links to his work here on the barn!!!
I would expect the original 46-48 armature to have a groove at the end of the threads for the clip that prevents the threaded pulley from unscrewing.
the ones without the groove were for pulleys held on with a nut