Simon, all the '55-60 Polars had the red glass. It blends in real well in the Fall woods
The tip overlays allow for more rounded string grooves, which reduces stress risers and prolongs string (and bow) life. The alternative to overlays is to round into the fiberglass more, which reduced the tip strength.
To keep it close to original, use paper micarta. There were instructions on how to make some here a few weeks ago. You can also use glass, or just wood. I replaced tip overlays on a '59 Polar with maple and rosewood (gasp).