5/30 is the earliest know date stamps for the US B models Photoed is one of my homemade etched globes that looks similar to an original. Base stamp: Nickel plated roll seam collar: Keyed frame and bail: Typical B valve and 4 piece screened F/A tube: Eccentric assembly with long eccentric block: Square hole valve knob and brass direction disk: Burner assembly ready for installation: Lighting the night Thanks for looking