At first, the dials have slightly raised center. Starting around 1949, the dial was made flat. Silver finish dial with modified stag beetle hands.
Examples examined:
12 45 Dial has raised center, nickel plated movment (eBay)
9 46 Dial has raised center, nickel plated movement
8 48 Dial has raised center, nickel plated movement
11 48 Dial has raised center, nickel plated movement
12 48 Dial has raised center, nickel plated movement
3 49 Flat dial, nickel plated movement (eBay 7-30-12)
9 51 Flat dial, brass movement
7 53 Flat dial, brass movement
7 56 Flat dial, brass movement with blue barrel bridge