1949 Chevy Taillight Lens made of plastic is listed here. The lens is a reproduction of the original 1949 GM replacement lens, red in color. This plastic taillight lens is not being made today so it is a NOSR “new old stock replacement” lens from the 50’s. Glass or plastic does not matter for 1949 Chevy, neither one is being made today. The main reason the 1949 lens is not being made today “in my opinion” is because the 1950 is much more popular so sales of the 1949 lens are much lower. Also the 1950 taillight lens is more popular and fits both years. The original GM lens supplied in 1949 was made of glass.
Glass lenses have several things that make them better than a plastic lens
1. They will normally look brighter when the brakes are applied.
2. If you convert your electric system to 12 volt and use a “bright” bulb, the plastic can melt.
3. After time the plastic will tarnish and become dull, glass stays shiny longer