Hey there! Great find!
Here is what I can help with...the pedals, grips, and sissy bar are not original to the bike. However, it is a fairly rare one, the gold color versions of the Rail don't pop up very often. The gold color bike is their 3-Speed version, where the 5-Speeds were violet. Kind of a rare one!
It is most likely a 1967 bike. The serial number will be on the dropout on the non-chain side. It will begin with 7H I would think, for 1967, made in Celina, OH.
The sissy bar was made by All American Products and was an accessory sissy bar from the 1960's. They made parts with the "Bronco" label, some sissy bars and seats. They were located in Chicago. I might remove the sissy and sell that separately from the bike, but it's is up to you. It might be a $80-100 item by itself.
The sissy bar pad is not original to the bike either, it is probably Made in Japan, and was another accessory item sold in the 1960's. I might sell that separately too. It might be a $20-40 item alone.
$150 to $800 for it is quite a difference for the bike haha! I think it might be a $400-500 bike. The paint looks great but the seat is a bummer with the rust spots in the material. Those spots on the seat won't clean off. The good things on the bike are the shifter and the tires, the shifters are hard to come by, and the tires too, and those are original to the bike.
Good luck with it! PM me directly if you have any questions!