For sale here is a new 1941-1946 Chevrolet Truck Speedometer/Gauge lens.  Available in miles per hour or kilometers per hour. 

This also fits a 1940 Chevrolet Passenger car.  The third photo shows a custom glass I did for a 40 Chev car owner who's gauges had been moved to a different location. The cost was $79.00.

I make lots of other lenses so have a look and ask if you don't find what you need.  

Satisfaction guaranteed.