I knew I din't have enough information together when I posted this! The backbone has been cut out and completely removed from the frame. There is a stub cut off flush with the headstock casting, but completely removed from seat area casting. It looks like someone tried to lower the seat height by cutting the twin vertical tubes, removing the back bone and then realized you can't very easily lower the headsock casting. No, I have not tried a spark test on the casting, I just assumed it was cast iron...