I have the mechanism and assembly, but (2) of the springs are missing/broke.
Does anyone know if those springs are optional to buy or if anyone has a working assembly laying around they want to sell.

You might check with one of these guys. They should have just what you need and could answer any questions for sure. If you haven't found what you needed already.

https://firstgenfirebird.org/f-a-q/hood-tach-servicing/

Brett - 67 Drop Top 455!