Breitling - Vintage Mille Miglia

[om1d]

Wanted to get some advice on the vintage Breitling Mille Miglia watches. I've recently purchased one (see pictures attached) and would like to understand the following:

- Authenticity of the watch (dial, casing etc) - 18K gold
- Strap: what would the original strap have looked like
- Story behind the Mille Miglia series: were these produced for the race drivers in the Mille Miglia race exclusively? Were they available commercially?
- Quantity: how many would have been produced?
- Value: where would you value a good condition (working) Breitling Mille Miglia watch?

Many thanks for all of your help!