Wow, your car is really coming along nicely. And it looks amazing, well done.
I like the upholstery on the seats. Is that a tweed fabric on the bolsters and inserts? I am doing something very similar on a set of seats for another (non-Fiat) project' black tweed bolsters with grey print inserts. If you have a clear close up pic of the fabric I'd like to see it.
That switch is definitely something a PO has added. No telling what it was used for; a horn, a replacement for a faulty start switch, some auxiliary lighting, etc.