You are correct. I'm pretty sure that it is the original seat pan. It was mounted with some makeshift brackets. The bike that I have is most likely a Model B that didn't come with the jackshaft/torque converter set-up or front brakes since there is no evidence of either. I do not have the original brake pedal, handlebar neck, chain guard, or lights. Besides those things I think it's all there. And, I certainly don't have the original engine. I'd just like to know, for sure, what year it is.